Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance
The suicidal behavior is regarded as the act by which a person seeks to take his life, being aware of the consequences of his action. In our review, besides describing the main introductory aspects for the concept of suicide, we focus our attention on the main neurophysiological and genetical mec...
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Інститут фізіології ім. О.О. Богомольця НАН України
2016
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| Цитувати: | Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance / M. Padurariu, R. Prepelita, A. Ciobica, R. Dobrin, D. Timofte, C. Stefanescu, R. Chirita // Нейрофизиология. — 2016. — Т. 48, № 4. — С. 342-351. — Бібліогр.: 72 назв. — англ. |
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irk-123456789-1483282019-02-19T01:30:19Z Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance Padurariu, M. Prepelita, R. Ciobica, A. Dobrin, R. Timofte, D. Stefanescu, C. Chirita, R. Обзоры The suicidal behavior is regarded as the act by which a person seeks to take his life, being aware of the consequences of his action. In our review, besides describing the main introductory aspects for the concept of suicide, we focus our attention on the main neurophysiological and genetical mechanisms relevant for this extremely difficult to manage and controversial behavior. Moreover, considering the latest interests in the current literature on the relevance of central oxytocin to various superior cognitive behaviors, we will also make a short description on how important effects of oxytocin could be in the context of suicidal behavior. Суїцидальна поведінка – це дії, в результаті яких особа намагається позбавити себе життя, усвідомлюючи наслідки таких дій. У даному огляді, окрім опису основних загальних аспектів концепції суїциду, ми концентрували увагу на основних нейрофізіологічних та генетичних аспектах, котрі мають відношення до цього вкрай важко контрольованого та повного протиріч типу поведінки. Окрім того, враховуючи велику цікавість, яку викликає в сучасній літературі задіяність центральної окситоцинової системи в контроль когнітивної поведінки вищих типів, ми надали короткий опис того, наскільки ефекти окситоцину можуть бути важливими в контексті суїцидальної поведінки. 2016 Article Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance / M. Padurariu, R. Prepelita, A. Ciobica, R. Dobrin, D. Timofte, C. Stefanescu, R. Chirita // Нейрофизиология. — 2016. — Т. 48, № 4. — С. 342-351. — Бібліогр.: 72 назв. — англ. 0028-2561 http://dspace.nbuv.gov.ua/handle/123456789/148328 616.89–008.441.44:612.434.73 en Нейрофизиология Інститут фізіології ім. О.О. Богомольця НАН України |
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Обзоры Обзоры |
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Обзоры Обзоры Padurariu, M. Prepelita, R. Ciobica, A. Dobrin, R. Timofte, D. Stefanescu, C. Chirita, R. Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance Нейрофизиология |
| description |
The suicidal behavior is regarded as the act by which a person seeks to take his life, being aware
of the consequences of his action. In our review, besides describing the main introductory
aspects for the concept of suicide, we focus our attention on the main neurophysiological
and genetical mechanisms relevant for this extremely difficult to manage and controversial
behavior. Moreover, considering the latest interests in the current literature on the relevance
of central oxytocin to various superior cognitive behaviors, we will also make a short
description on how important effects of oxytocin could be in the context of suicidal behavior. |
| format |
Article |
| author |
Padurariu, M. Prepelita, R. Ciobica, A. Dobrin, R. Timofte, D. Stefanescu, C. Chirita, R. |
| author_facet |
Padurariu, M. Prepelita, R. Ciobica, A. Dobrin, R. Timofte, D. Stefanescu, C. Chirita, R. |
| author_sort |
Padurariu, M. |
| title |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance |
| title_short |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance |
| title_full |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance |
| title_fullStr |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance |
| title_full_unstemmed |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance |
| title_sort |
concept of suicide: neurophysiological/genetic theories and possible oxytocin relevance |
| publisher |
Інститут фізіології ім. О.О. Богомольця НАН України |
| publishDate |
2016 |
| topic_facet |
Обзоры |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/148328 |
| citation_txt |
Concept of Suicide: Neurophysiological/Genetic Theories and Possible Oxytocin Relevance / M. Padurariu, R. Prepelita, A. Ciobica, R. Dobrin, D. Timofte, C. Stefanescu, R. Chirita // Нейрофизиология. — 2016. — Т. 48, № 4. — С. 342-351. — Бібліогр.: 72 назв. — англ. |
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Нейрофизиология |
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NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4342
ОБЗОРЫ
UDC 616.89–008.441.44:612.434.73
M. PADURARIU1, R. PREPELITA1, A. CIOBICA2,3, R. DOBRIN1, D. TIMOFTE1, C. STEFANESCU1, and R. CHIRITA1
CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES
AND POSSIBLE OXYTOCIN RELEVANCE
Received May 15, 2015
The suicidal behavior is regarded as the act by which a person seeks to take his life, being aware
of the consequences of his action. In our review, besides describing the main introductory
aspects for the concept of suicide, we focus our attention on the main neurophysiological
and genetical mechanisms relevant for this extremely difficult to manage and controversial
behavior. Moreover, considering the latest interests in the current literature on the relevance
of central oxytocin to various superior cognitive behaviors, we will also make a short
description on how important effects of oxytocin could be in the context of suicidal behavior.
Keywords: suicide, neurophysiological and genetic mechanisms, oxytocin.
1 Gr. T. Popa University of Medicine and Pharmacy, Iasi, Romania.
2 Alexandru Ioan Cuza University, Iasi, Romania.
3 Center of Biomedical Research of the Romanian Academy, Iasi, Romania.
Correspondence should be addressed to D. Timofte
(e-mail: dantimofte@yahoo.com).
INTRODUCTION
THE CONCEPT OF SUICIDE
The suicidal behavior is regarded as the act by which
a person seeks to take his life, being aware of the
consequences of his action [1]. Thus, suicide can be
regarded as a rationally executed act, based on moral,
social, religious, philosophical and/or personal reasons.
Conversely, suicide may be seen as a pathological
act, which occurs during the development of various
mental disorders (e.g., depression, persistent delirium,
dementia, confusion, etc.), or in the context of an acute
existential crisis in which the manifestations may
take the form of an auto-aggressive anxious raptus.
These raptuses are spontaneous, unpredictable, and
are manifested extremely rapidly, as compared with
the premeditated suicide of patients with melancholic
depression or in the context of systematized deliria [2].
Overall, regardless of motivations and context (e.g.,
social, family, or personal), the concept of suicidal
ideation refers to a person’s thoughts to take his/her
own life.
The World Health Organization defines suicide as an
act by which an individual seeks for his/her physical
self-destroy, with the more or less authentic intention
to waste his/her life or being more or less conscious
of the rationale of the gesture [3]. Interpreted more
broadly, the concept of suicide can also refer to any
action, tendency, or behavior of self harm (including
the so-called “chronic suicide “ of drug addicts,
alcoholics, or individuals with mental anorexia) that
by certain self-destructive behaviors of repetitive
cyclical-nature attempts to finish the personal life.
Also, in a narrow interpretation, the suicide is the act
of global self-destruction, of sudden suppression of
one’s own life, intentionally, willfully, knowingly, and
considering death as a total and inexorable ending.
In fact, suicide is the expression of an acute crisis
of conscience that expresses a subjective-affective
tension between the individual and the group, favored
by situational factors, with the ability to precipitate
the autolytic gesture in a fragile and vulnerable
personality [4]. In this way, Douglas [5] defines
suicide from a double perspective, both psychological
and sociological, addressing rather a concept than
an operational definition. Douglas reveals the five
dimensions of the suicidal act, namely initiative,
motivation, intention, will, and desire. According
to Scripcaru et al. [6], the suicide definition would
represent a tempted or actual behavior expressing a
psycho-emotional tension between the individual
and the social group, triggered or precipitated by
circumstantial factors with a consciously designed
self-destruction idea. In addition, other theorists
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4 343
CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES AND POSSIBLE OXYTOCIN RELEVANCE
consider suicide a disruption of homeostasis in the
individual/environmental relation and deciphering its
code depending on the visibility and understandability
of its forms of expression. Thus, in some individuals
a death will is certain, while in others it is uncertain,
in some it is impulsive, in some it can be cyclical, in
some it is chronic, persistent, and in others the wish to
die is acute, transient, with or without a repeatability
trend.
The concept of suicidal behavior refers to the
technical support, consisting of the preparatory work
for staging the suicidal act, the steps and settling
the suicidal plan. Choosing the manner of ending
one’s own life is determined by many factors, such
as effectiveness, speed, ease of execution, imitation,
keeping physical appearance and bodily integrity,
availability of the suicidal method, and sometimes
also by limiting as much as possible the beforehand
suffering and anguish. To ensure the success of the
method, the most efficient approach will be adopted
in accordance with the availability and access to
certain types of methods. But ultimately, the choice of
the suicidal means is determined by the significance
of the act and the mental condition of the person at
the time when committing suicide. The effectiveness
of the chosen means is regarded as revealing the
authenticity of the suicide attempt. Traditionally,
it is considered that the main autolytic means are
traumatic (defenestration and shooting), asphyxia
(gas inhalation, submersion, strangulation), and toxic
(ingestion of the respective substances) [7].
Also, certain aspects due to cultural differences
should be mentioned when choosing other variants
of self harm. Thus, while in China the poisoning
with opium and salts of arsenic is frequent, in Japan
the traditional seppuku was replaced by the use
of firearms, while in France the order of the most
commonly used methods is hanging, drowning, and
using firearms [8].
Below, we will briefly review the main methods
used in suicidal behavior. One such method involves
exsanguination by damaging the easy to access
arteries (radial, ulnar, carotid, or femoral), wich
causes hypovolemia below the critical level leading
to a circulatory collapse. Chronic suicide attempts,
parasuicide, or self-mutilation attained in the same
manner can be assessed by looking for traumatic
marks (scars) at the level of these arteries. Also
typical of this type of conduct is a large number of
injuries [9]. In addition, suicide by hanging involves
two types of mechanisms, depending on the length of
the drop. Thus, one of the mechanisms that occurs in
the short drop achieves death by hypoxia through the
compression of the carotid artery and jugular vein. For
the longer drops, vertebral fractures can occur, often in
the C5-C6 vertebrae, which cause death or paralysis in
the survivors [10].
Another autolytic method used by suicidal persons
is by jumping from high buildings, through windows
(defenestration), from bridges or cliffs. This is frequent
especially in the areas with increased accessibility to
these kind of methods. For example, in Hong Kong,
where there are a large number of high buildings, more
than half of the deaths by suicide are executed through
this method [11]. This autolytic approach is associated
with a high risk of severe consequences in the case
of a failed suicide, such as paresis, paralyses, bone
fractures, and severe damages to internal organs.
Another method of suicide used relatively frequently
involves the use of firearms. The use of firearms
in suicide attempts is more common in people who
routinely possess firearms, but also in countries with
permissive legislation on firearms possession [12].
However, it is doubtful to believe that the legislative
restrictions concerning the firearms possession would
lead to lower overall rates of suicide. The decrease
of certain methods of suicide by reducing the access
possibilities could lead to increased rates of other
types of methods as a compensatory mechanism.
Suicide produced by asphyxia is often achieved
by exposure to certain toxic gases, such as carbon
monoxide. This produces a quick death as it rapidly
induces unconsciousness state preventing an eventual
change of mind of the suicidal person [13].
Suicide by drowning is relatively rare, as compared
to other autolytic methods. A study conducted on the
US population reported less than 2% of suicide deaths
as caused by drowning. The mechanism of death
consists in the acute oxygen deprivation of the brain
by immersion in water that impedes the breathing
process.
Other common suicidal methods include drug
overdose, traffic accidents, electrocution, or poisoning.
Also, as previously mentioned, the modern trend
concerning the growing use of hallucinogens suggests
that drug addiction can be a passive form of self-
distructive behavior. The chronic use of hallucinogens,
naturally, has strong negative consequences on health.
Very interestingly, a research on the places selected
for accomplishing the suicide reported that about 44%
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4344
M. PADURARIU, R. PREPELITA, A. CIOBICA, et al.
of suicidal acts are performed at home; public places;
hotels, and working places are less preferred [14]. In
this way, such aspects could represent an important
lead when intending to oversee and prevent a person
known with a high risk of suicide.
According to Stengel [15], the genuine suicidal act
unfolds as follows: the occurrence of one’s decision to
end his/her lives or the impulsive action to self-kill,
using for this the most efficient methods and taking all
the safety measures that nobody will interfere. If death
occurs, it is considered a successful suicide attempt;
if the person survives, the act would be considered a
failed suicide one. As death is the only purpose of the
act, it should be considered the criterion for success.
The failure may be caused by any of the following:
motivation is not strong enough; the act has not been
well prepared (either due to lack of total conviction on
completing the act, or because of lack of knowledge on
the limits of the chosen method, lack of judgment, and
determination because of a mental illness). According
to these criteria, only a part of the accomplished
suicidal acts and only a small part of those unfinished
can be considered genuine acts of suicide. However,
even in the suicidal acts where the person is not fully
committed to end his life, a significant number of
cases come to completion, while the rest remain as
unclear trends or insufficient efforts, ending rather by
accident than by determination in action.
In this way, it could be stated that suicide is actually
the action of taking one’s own life, while a suicide
attempt or non-fatal suicidal behavior refers to self-
harming in order to take one’s own life, but that does
not lead to death. The differences between assisted
suicide and euthanasia, types of suicide that require
another person in order to be completed, should also
be mentioned. The assisted suicide occurs when a
person indirectly helps another to end his/her life, by
providing advices or means for the suicidal act, and it
differs from euthanasia, in which the other person is
playing a more active role in causing someone’s death.
In most cases, the completed suicide follows
repeated suicide attempts. A large number of patients
who died by suicide have a history of autolytic
suicide attempts or even suicidal ideation. Sometimes,
the suicidal people have in their family relatives
with suicide attempts or completed suicide, which
may account for models in their autolytic behavior.
Attempted suicide is actually the missed (failed)
suicidal act. The attempts may be the expression
of a compulsion, can have a demonstrative value,
or embody the expression of a punitive act. In fact,
clinical studies have shown that suicidal attempts are
8-10 times more common in young people than in
adults and about 5-10 times more often in women than
in men, the ratio decreasing with age [16].
In general, the suicidal tendencies are explained by
self-aggression, and the suicidal impulse explains the
suicide as an expression of an irresistible trend. The
irresistible suicidal impulse drives the individual to
make use of the first means he/she comes across, in
opposition to the former suicide plan. Often, the suicide
attempts leave long-term physical consequences,
which can be very different depending on the autolytic
method. Thus, some serious physical sequelae may
occur following autolytic attempts, such as mutilation,
fractures, severe locomotor, psycho-sensorial, or
mental disabilities (e.g., dementia after oxygen
deprivation), or functional disabilities (paralysis).
In this way, Biberi [17] considers the suicide
as a bio-psycho-social dimensional phenomenon
representing an act requiring the deviation for one
of the most deeply rooted instinct of the biological
structure. In a dramatic situation in which the vital
instinct is denied (out of which the subject does not
see any escape), suicide becomes the only solution to
avoid its unbearable conditions.
Also, according to Menninger [18], the suicide
encompasses the three desires that could foster a
suicidal act, namely the desire to kill, the desire to be
killed, and the desire to die. The desire to kill may be
directed not only against an object of love, but also
against the internal space. In fact, the conclusions of
some long-term clinical trials showed that suicide is
sometimes intended to destroy the lives of survivors,
as an act of revenge against the others. For example,
depressed patients often feel that suicide is the only
satisfactory revenge. Sometimes, this act is directed
against the parents, brothers, or the partner, and the act
is intended to produce suffering of the latter.
In other cases, aggression plays a much more
modest role in terms of motivating the suicide. Thus,
Fenichel [19] noted that suicide could mean the
fulfillment of a desire to reunite. Losing a loved one
is often behind suicidal behavior, and many suicidal
patients exhibit strong desires of dependence on the
lost person. From this point of view, the suicide may
be a regressive desire to reunite with a lost figure.
Sometimes, a pathological process of mourning is
involved, especially in attempts to commemorate the
death of a loved one. In this way, there are some ideas
that it could be a correlation between suicide and the
commemoration for the death of a parent.
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4 345
CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES AND POSSIBLE OXYTOCIN RELEVANCE
EPIDEMIOLOGICAL ASPECTS
The suicidal behavior is considered a psychiatric
emergency. Virtually, all psychiatric disorders can
sometimes generate either spontaneous auto-aggressive
and hetero-aggressive outbursts on a background
of high psychoemotional tension or, by contrary,
planned and idealized previously of the act. The
demographic analysis of the completed suicide shows
that, generally, the chosen suicide method depends on
the geographical area and availability of the method,
but also on certain personal factors. Among the chosen
suicide methods, the most commonly used seems to be
hanging, probably due to the easy access to material,
as compared to other methods. A study conducted in
56 countries found hanging as the prevailing method
of suicide in most countries [20]. This method was
employed by 53% of men and 39% of women [21].
Also, a relatively high number of suicides have
been recorded as a result of drug overdose, the cause
of about 60% of the suicide cases in women and 30%
in men [22]. Frequently, the suicide by overdose is
not previously planned, or it occurs during a period
of acute ambivalence. The difference between sexes
regarding this method supports the idea of a higher
frequency of planned suicide in men. The most often
tried methods differ from the most often successful
methods; up to 85% of suicide attempts in the
developed countries consist in ingesting an overdose
of drugs [23].
Moreover, the studies are generally indicating
different percentages regarding the type of suicidal
methods. A meta-analysis concerning the most frequent
suicide methods identified shooting in 80-90% cases,
drowning 65-80%, inhalation of an exhaust gas 40-
60%, jumping from height 35-60%, and pesticides
6-75% [24].
Also, a regional analysis of the methods and
frequency of suicide methods showed that, 57%
of suicides in the United States, involve the use of
a firearm, the percentage being distinctly higher in
men than in women. A second cause of suicide in
men is hanging, while in women this is poisoning.
In Switzerland, the most common suicidal method is
the suicide by hanging [25], while in Hong Kong and
Singapore, suicide by jumping from height is very
common, with rates ranging from 50% in Hong Kong
to 80% in Singapore [24]. Moreover, in Japan, suicide
by hanging is the most common method [26], but also
the traditional suicide by disembowelment known as
seppuku, or harakiri, is still used nowadays.
NEUROPHYSIOLOGICAL MECHANISTICS
AND THEORIES OF SUICIDE
In this way, among the most investigated biologi-
cal systems related to the suicidal behavior is the se-
rotonergic system. The researches focused on the
levels of serotonin, its metabolite (5-hydro xy-
indoleacetic acid, 5HIAA), its receptors (5HT2A), and
its carrier (5HTT) in platelets. There are also several
studies that have compared the whole blood- or plate-
let- levels of 5HT in patients with mood disorders and
a suicide risk. Thus, Roggenbach et al. and the group
led by Mann [35, 36] reported decreased serotonin
levels in blood platelets in suicidal patients with real
suicide attempts, as compared to patients with suicid-
al ideation only or without autolytic attempts and also
non-suicidal patients.
Also, Almeida-Montes et al . [37] reported
significantly decreased serum levels of 5HT in
depressed patients who attempted suicide, when
compared with depressed patients without suicide
attempts. Moreover, in a meta-analysis by Lester [38]
on a CSF serotonin metabolite, the authors found
significantly lower levels of 5HIAA in the patients
with previous suicide attempts, as well as in those who
subsequently committed suicide or attempted this. In
addition to low CSF 5-HIAA levels, the persons who
committed suicide showed also an increased number
of binding sites for serotonin. In terms of the autolytic
ideation intensity, Tyano et al. [39] also found a
negative correlation between plasma levels of 5HT and
the severity of suicidal behavior in patients.
In addition, determining the 5HT receptors in
suicidal patients or those with affective disorders
led to the extensive study of the 5HT2A receptor. In
this way, the 5HT2A receptor seems more likely to
be modified in patients with depressive disorders and
suicidal ideation. In general, the 5HT2A receptors
were examined in blood platelets by radioligand
binding techniques, and the pharmacological profile
of the 5HT2A receptors in the platelets appears to be
very similar to that observed in the brain [39].
Even more, Pandey and his collaborators [40]
studied the platelet levels of 5HT2A receptors in
patients with affective disorders with and without
autolytic ideation. In the first instance, the level of
5HT2A receptors was found to be higher in depressed
patients, as compared with control subjects. Also, the
5HT2A receptor density was even higher in depressed
patients with suicidal behavior, when compared to
depressed patients without suicidal ideation. When
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4346
M. PADURARIU, R. PREPELITA, A. CIOBICA, et al.
analyzing whether the increase of the 5HT2A receptors
in the depressed suicidal patients is independent or
not diagnostic and by examining the 5HT2A receptor
levels in patients with various psychiatric diagnoses
(such as depression, bipolar depression, manias,
schizoaffective disorder, or schizophrenia), the authors
also noted that the average receptor density in the total
group of suicidal patients was significantly higher than
that in non-suicidal patients or in the control group.
Also, the receptor density was significantly higher in
the patients with psychiatric disorders and autolytic
ideation, as compared with control subjects. In
addition, this study [40] suggested the increase of the
platelet 5HT2A receptor density in suicidal patients,
irrespective of the diagnosis.
In addition, numerous evidences supported the
involvement of the 5-HT1A receptor in the formation
of suicidal behavior. The important role of 5-HT1A
receptors in suicidal behavior was in this way assayed
by studying the changes of these receptors in the
postmortem brains of the suicide victims. In this
way, the results showed that binding to the 5-HT1A
receptors was found to increase in the cortex of
suicidal patients with major depression, but no change
in binding to these receptors was observed in the
frontal lobes, occipital cortex, hippocampus, and
amygdala of depressed suicidal patients [41, 42]. These
discrepancies could be explained by the intervention
of other factors, such as gender, presence or absence
of affective disorders, or ethanol consumption (as we
would like to insist immediately on this important
factor).
Also, the involvement of the serotonergic system
in suicidal behavior seems to correlate with specific
nervous areas, such as the forebrain, medial prefrontal
cortex, orbitofrontal cortex, amygdala, and nucl.
accumbens [43]. In this way, the postmortem studies of
suicidal persons reported fewer serotonin transporters
in the prefrontal cortex, hippocampus, occipital cortex,
and brainstem [44].
We should also mention that the relationship
between serotonin and aggressiveness [45] is an
important aspect in studying the neurobiological
underpinnings of suicide, especially in violent suicide
cases. In fact, suicidal behavior is influenced by many
biological variables that modify the serotonergic
neurotransmission, including the psychosocial stress,
traumatic experiences, pathological personality traits,
disorders, or the alcohol abuse [46, 47].
Regarding the latter mentioned aspect, it is well
known that alcoholism can be found in most psychiatric
disorders and is often having an etiopathogenic
role. Thus, affective disorders, anxiety, psychosis,
dementia, and personality disorders frequently
are accompanied by alcoholism as a co-morbidity.
Moreover, some mental disorders are caused by
prolonged or abusive alcohol consumption; other
disorders appear as withdrawal phenomena, while
in many cases alcoholism aggravates a preexisting
psychiatric conditions. In some cases, alcohol
consumption is intended to improve the psychiatric
symptoms, such as anxiety, depression, psychosis,
hypnic disorders, or side effects of medications [48].
Among the psychiatric disorders, depression and mood
disorders are particularly associated with alcohol
abuse. Of course, patients suffering from a major
depressive disorder are at increased risk of suicide.
What is important in the present context, is that
studies on patients who died by suicide showed that in
30% of cases the blood alcohol level was close to or
over the legal limit at the time of suicide, and half of
them suffered from major depression [49]. Moreover,
alcohol abuse is also suspected to dramatically (by
an order of magnitude) increase the risk of suicidal
behavior [50].
Sti l l , the relat ionship between alcoholism,
depression, and suicidal behavior is complex
and clearly supported on the biochemical level.
Some CSF analysis showed abnormalit ies of
serotonin metabolism, through the dosing of the
5-hydroxyindoleacetic (5HIA) metabolite in depression
and particularly in suicidal behavior. Moreover, low
levels of this serotonergic metabolite are encountered
in impulsivity and aggressive excesses, which are
manifested especially during the consumption of
ethanol. As was many times mentioned, the elements
of impulsivity and aggression are known to correlate
with suicidal behavior [51].
Moreover, the risk of suicide for the patients
addicted to alcohol is 60 to 120 times higher than that
in the general population [52]. The gender distribution
shows also a much higher frequency in men, in
relation to the use of alcohol before committing the
suicidal act [53]. Also, alcohol consumption can cause
disinhibition and increased impulsivity, which could
favor mobilization to complete the suicidal act.
GENETIC STUDIES
With regard to suicidal behavior, the research on
families, twins, and adoptions provided evidence
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CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES AND POSSIBLE OXYTOCIN RELEVANCE
on the significant heritability of suicide and suicide
attempts, independent of the family transmission for
the major psychiatric disorders. Thus, for twins the
estimated heritability for suicidal risk ranges between
21-50%, while for the broader phenotype of suicidal
behavior (attempts, suicidal thoughts, and plans) it is
30-55%, depending on the type of study [27]. Also,
some genetic researches have attempted to identify
the genes involved in suicide and suicidal behavior
by studies of genetic association or following specific
single nucleotide polymorphisms for studies of
association.
Candidate genes for association studies were gener-
ally selected on the basis of evidence from neurobio-
logical studies in suicidal patients. Therefore, the se-
rotonergic system has been extensively investigated in
relation with other target systems, including the dopa-
minergic and noradrenergic ones, derived neurotrophic
factor, and, more recently, the genes related to hypo-
thalamic-pituitary-adrenal (HPA) axis. Apparently, the
environment could be also very influential in this mat-
ter, especially during the development.
Moreover, the neurobiological evidences indicated
a considerable serotonergic dysfunction in suicide
cases, while the genetic research has been mainly
focused on genes related to the serotonin system. At
the molecular level, serotonin appears to be one of
the key neurotransmitters involved in the formation
and control of suicidal behavior. Thus, among the
genes encoding proteins involved in the serotonergic
neurotransmission in suicidal persons, the most
consistent scientific evidences are referring to the
tryptophan hydroxylase gene, especially in the case of
violent suicidal behavior [28]. In addition, promising
studies have examined the serotonin receptors,
monoamin oxidase receptors, serotonin 2a and 2c
receptors, and tyrosine hydroxylase.
Thus, the genetic factors seem to be a significant risk
factor, apart from the environmental aspects of suicidal
behavior. Moreover, epidemiological and genetic
studies indicated a familial aggregation of suicidal
behavior, with a fivefold greater risk for relatives of
persons with suicidal behavior [29, 30]. In this way,
Voracek et al. [27] reported a significantly higher rate
of concordance for suicidal behavior in monozygotic
twins (24.1%), as compared to dizygotic ones (2.8%).
Also, the neurobiological and genetic studies
have suggested that, generally, the suicidal behavior
results from a complex interaction of multiple genes
and environmental factors. The suicide attempts in
this suicidal model are considered a combination of
stressors and personality traits. Basically, for this
model, the innate genotypic and phenotypic profile of
the individuals determines their inability to cope with
stressors [31]. Also, many specific genetic variants
may exert additive effects on suicidal behavior by
intensifying the impact of a stressor.
The researchers who analyzed the importance of
genes in suicide have primarily focused on the genes
involved in the serotonergic, adrenergic, noradrenergic,
and dopaminergic neurotransmitter systems by the
analysis of the samples taken from postmortem brain
tissues of persons who completed suicide. Thus,
a strong evidence supporting the association with
suicidal attempts was identified for one of the most
commonly studied suicide gene, the S allele of the
serotonin transporter, but this was not found with
respect to completed suicide [31]. Moreover, a study
published in 2007 on bipolar patients highlighted
the importance of the 2p12 locus in the patients with
suicidal attempts, supporting previous studies on the
relevance of this locus to suicidal behavior [32].
Also, the results of some studies have suggested the
involvement of the dopaminergic system, in particular
of the D2 receptor, in the expression of suicidal
behavior. Thus, a study on 120 patients with suicidal
attempts assessed the association between these
attempts and two types of functional polymorphisms
of the dopamine D2 receptor gene (DRD2), TaqIA
and 141C, as compared with the control group. It
was demonstrated [33] that there are significant
differences of the frequency of the allele-141C Ins/
Del and TaqIA polymorphisms between patients and
the healthy control group, suggesting that DRD2 gene
polymorphisms might be involved in the biological
susceptibility to suicidal behavior.
Also, cholecystokinin (CCK) could play a significant
role in suicidal behavior. In this way, Shindo et al. [34]
found a strong association between the gene for CCK
(the latter as a central nervous system neurotransmitter
found inside certain dopaminergic neurons and also
modulating dopamine release) and suicidal behavior,
by analyzing the DNA of 154 suicide victims, as
compared with 328 control subjects. The statistical
analysis demonstrated an association between the
polymorphism of CCK 196G/A and suicide occurance
only in men of the studied group, and not in women.
OXYTOCIN RELEVANCE
As we mentioned at different other occasions [45],
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M. PADURARIU, R. PREPELITA, A. CIOBICA, et al.
within the last few years there was an increase in the
number of research groups and general interest for
better understanding of the possible beneficial effects
exerted especially by intranasal oxytocin on the main
neuropsychiatric diseases, with a focus on schizophre-
nia [54], depression [55], frontotemporal dementia
[56], autism [57], or anxiety-related behavior [58].
In relation to suicidal behavior, there are also some
interesting and controversial aspects to be mentioned
for the possible influence exerted by oxytocin.
These possible correlations basically started in a
study performed in 2009 by the Lee et al. group [59],
which mainly focused on the relations between CSF
oxytocin, aggression, and personality disorder, but also
did manage to increase awareness on possible relations
between oxytocin and suicidal behavior through only
4 patients with suicide attempts vs. 54 controls (non-
suicidal attempters) by using the specific LHA scale.
One of the most important studies in this research
area regarding the interactions between oxytocin
and suicide was performed in 2012 by the Swedish
group of Jokinen et al. [60], who clearly demonstrated
decreased levels of oxytocin in the CSF obtained
by lumbar punctures of 28 medication-free suicide
attempters vs. healthy controls [60]. Moreover, the
aforementioned group did manage to find some
important correlations between most of the specific
scales they have used to asses suicidal behavior (e.g.,
the Beck Suicide Intent Scale, the Freeman scale,
or the Karolinska Interpersonal Violence Scale) and
both CSF and plasma oxytocin levels, but only in men
and not in women. However, the authors also found
correlations between aggressive/violent behavior and
oxytocin levels only in female suicide attempters (we
would like to insist immediately on the relevance of
this aspect). In fact, our research group also described
earlier the complex interaction between aggressive
behavior and oxytocin activities [45].
On the other hand, there are still controversies
in this area of research, since some research groups
failed to find any correlations between the oxytocin
levels and psychiatric patients with and without recent
suicide attempts. For example, this was the Deisen-
hammer et al. group [61], which found no differences
in terms of plasma oxytocin concentrations between
people with affective disorders and suicide attempts
within the last 12 months vs. people with affective dis-
orders but no suicide attempts.
Dissimilar results obtained by various research
groups could be explained by differences in the estab-
lished research protocol (e.g., oxytocin levels could be
quite different in the CSF vs. plasma, as was in the two
studies mentioned above), different medication, or the
fact that suicidal behavior can exhibit extremely im-
portant gender differences [60, 62].
Mechanistically speaking, the implications of
oxytocin in suicidal behavior could also be explained
through the important effects exerted by oxytocin in
stress modulation, e.g., by decreasing cortisol levels.
This could be done by inhibiting the HPA axis [63].
Important correlative results between the decreased
levels of plasma oxytocin and borderline personality
disorder were also observed only in women patients
[65]. This could be quite relevant in the present
context, especially considering that certain behaviors,
such as self-injury, suicidal, or parasuicidal one, are
for a long time accepted in patients suffering from
borderline personality disorder [65]. In addition,
the aforementioned Bertsch group [64] showed
correlations between traumatic childhood experiences
(e.g., emotional neglect or abuse and aggressive
behavior) and oxytocin concentrations in the plasma.
In fact, in direct relation to the traumatic childhood
experiences, the group of Chatzittofis [66] quite
recently (in 2014) showed that there is also an
interesting relationship between the CSF/plasma
oxytocin concentrations in suicide attempters and the
role of a childhood trauma and revictimization. In this
way, in 28 medication-free suicide attempters, these
authors, using evaluation scales (such as the Karolinska
Interpersonal Violence Scale), showed important
correlations between revictimized suicide attempters
and plasma oxytocin levels. Still, the authors failed
to find any correlation between interpersonal violence
exposure as a child vs. CSF and/or plasma oxytocin
[66]. However, it is generally accepted in the literature
that a strong correlation between childhood abuse and
oxytocin concentration should exist [67].
Recent studies also described important interactions
between CSF oxytocin concentrations and the
schizophrenic pathology, especially in men [68]. This
could be extremely relevant, especially considering
the very well known and extensively accepted
relationship between schizophrenia and suicidal
behavior [69]. Anyway, the schizophrenic pathology
has attracted an increased interest from the most
important worldwide names in the effects of intranasal
oxytocin studies, as, e.g., from the group of Guastella
et al. [72]. These authors showed that only one dose of
oxytocin nasal spray could facilitate social cognition
in schizophrenia [54]. Still, there are controversies
also in this area of research with previous reports
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4 349
CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES AND POSSIBLE OXYTOCIN RELEVANCE
stating significant correlations [70] or no correlations
at all [71] between the CSF levels of oxytocin and
schizophrenic pathology. One of the explanations for
this aspect could be represented by a complex nature
of the reactions, existing between administration
of antipsychotics in schizophrenia and the oxytocin
concentration (e.g., they might actually decrease the
levels of oxytocin [72]).
* * *
In our paper we, besides describing the main
introductory aspects for the concept of suicide,
focused our attention on the main biological and
genetical mechanisms relevant for the suicidal
behavior. Moreover, considering the latest interests
in the current literature on the relevance of central
oxytocin in various superior cognitive behaviors, we
also desribed how important oxytocin could be in the
context of suicidal behavior.
Acknowledgments. M. Padurariu, A. Ciobica, and
R. Dobrin are supported by the PN-II-RU-TE-2014-4-1886 grant
called “A complex study regarding the relevance of oxytocin
administration in some animal models of neuropsychiatric
disorders,” No. 120, 01/10/2015 (Romania).
This publication is a review of the literature data; thus, it
does not require the confirmation of compliance with ethical
standards for experimental works.
The authors, M. Padurariu, R. Prepelita, A. Ciobica,
R. Dobrin, D. Timofte, C. Stefanesku, and R. Chirita, confirm
that they have no conflicts of any kind related to the commercial
or financial problems, relations with organizations or persons,
which could in any way be associated with the investigation,
and with the relationship of the co-authors of the article.
М. Падураріу1, Р. Препеліта1, А. Ціобіка2,3, Р. Добрін1,
Д. Тімофте1, К. Стефанеску1, Р. Чіріта1
КОНЦЕПЦІЯ СУЇЦИДУ: НЕЙРОФІЗІОЛОГІЧНІ ТА
ГЕНЕТИЧНІ ТЕОРІЇ ТА МОЖЛИВИЙ ВПЛИВ СИСТЕМИ
ОКСИТОЦИНУ
1 Університет медицини і фармації ім. Гр. Т. Попа, Ясси
(Румунія).
2 Університет ім. А. І. Куза, Ясси (Румунія).
3 Центр біомедичних досліджень Румунської Академії,
Ясси (Румунія).
Р е з ю м е
Суїцидальна поведінка – це дії, в результаті яких особа на-
магається позбавити себе життя, усвідомлюючи наслідки
таких дій. У даному огляді, окрім опису основних загаль-
них аспектів концепції суїциду, ми концентрували увагу на
основних нейрофізіологічних та генетичних аспектах, котрі
мають відношення до цього вкрай важко контрольованого та
повного протиріч типу поведінки. Окрім того, враховуючи
велику цікавість, яку викликає в сучасній літературі заді-
яність центральної окситоцинової системи в контроль ког-
нітивної поведінки вищих типів, ми надали короткий опис
того, наскільки ефекти окситоцину можуть бути важливими
в контексті суїцидальної поведінки.
REFERENCES
1. K. Hawton, K. van Heeringen, “Suicide,” Lancet, 373, 1372-
1381 (2009).
2. M. Miller, D. Azrael, and C. Barber, “Suicide mortality in
the United States: the importance of attending to method in
understanding population-level disparities in the burden of
suicide,” Annu. Rev. Publ. Health, 33, 393-408 (2012).
3. J. Tintinalli, Emergency Medicine: A Comprehensive Study
Guide (Emergency Medicine Tintinalli), McGraw-Hill Comp.,
New York (2010).
4. A. Leenaars, Life Span Perspectives of Suicide, Plenum, New
York (1991).
5. F. Tudose, C. Tudose, and L. Dobranici, Psihopatologie şi
Psihiatrie Pentru Psihologi, Infomedica, Bucureşti (2000).
6. G. Scripcaru, V. Astarastoae, P. Boişteanu, et al., Psihiatrie
MedicoLegală, Polirom, Iasi (2002).
7. A. Ohberg, J. Lonnqvist, S. Sarna, et al., “Trends and
availability of suicide methods in Finland. Proposals for
restrictive measures,” Br. J. Psychiat., 166, 35-43 (1995).
8. G. Stone, Suicide and Attempted Suicide: Methods and
Consequences, Carroll & Graf New York (2001).
9. R. P. Dutton, “Pathophysiology of Traumatic Shock” Prog.
Search Anesth. Preoper Med. Pain, 20, No. 1, 7-10 (2001).
10. R. Maris, A. Berman, and M. Silverman, Comprehensive
Textbook of Suicidology, Guildford Press, New York (2001).
11. HKJC Centre for Suicide Research and Prevention, University
of Hong Kong, Method Used in Completed Suicide, Hong Kong
(2006).
12. A. Kellermann, F. Rivara, and G. Somes, “Suicide in the home
in relation to gun ownership,” New Eng. J. Med., 327, 467-472
(1992).
13. P. Hay, L. Denson, M. van Hoof, and N. Blumenfeld, “The
neuropsychiatry of carbon monoxide poisoning in attempted
suicide: a prospective controlled study,” J. Psychosom. Res.,
53, 699-708 (2002).
14. D. Dolinak, E. Matshes, and E. Lew, Forensic Pathology:
Principles and Practice, Acad. Press, Sandiego (2005).
15. G. Dingman, “Characteristics of patients with serious suicidal
intention who ultimately commit suicide,” Hosp. Com.
Psychiat., 39, 295-299 (1998).
16. K. Inder, T. Handley, A. Johnston, et al., “Determinants of
suicidal ideation and suicide attempts: parallel cross-sectional
analyses examining geographical location,” BMC Psychiat.
(2014).
17. F. Beauchamps and J. Childress, Principles of Biomedical
Ethics, Oxford Univ. Press, New York (1994).
18. W. Dwight and C. Chapman, “Reviewed Work: Man against
Himself, by Karl A. Menninger,” Science & Society. 2, 559-
562 (1938).
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4350
M. PADURARIU, R. PREPELITA, A. CIOBICA, et al.
19. H. Fenichel and D. Rapaport, The Collected Papers of Otto
Fenichel, Acad. Press, New York (1987).
20. V. Ajdacic-Gross, “Methods of suicide: international suicide
patterns derived from the WHO mortality database,” Bull.
World Health Organ., 86, 726-732 (2008).
21. R. O’Connor, C. Platt, S. Gordon, International Handbook of
Suicide Prevention: Research, Policy and Practice, John Wiley
and Sons, New York (2011).
22. J. Geddes, P. Jonathan, G. Rebecca, and M. Mayou, Psychiatry,
Oxford Univ. Press, Oxford (2003).
23. J. Tintinalli, Emergency Medicine: A Comprehensive Study
Guide (Emergency Medicine (Tintinalli), McGraw-Hill Comp.,
New York (2010).
24. P. Yip, “Means restriction for suicide prevention,” Lancet, 379,
2393-2399 (2012).
25. A. Regan, Culture and Mental Health Sociocultural Influences,
Theory, and Practice., Wiley-Blackwell, Chichester (2009).
26. E. Krug, World Report on Violence and Health, Vol. 1, World
Health Organ., Genève (2002).
27. M. Voracek and L. Loibl, Genetics of Suicide: a Systematic
Review of Twin Studies, Klin Wochenschr, Wien, 463-475
(2007).
28. T. Zupanc, P. Pregelj, and A. Paska, “Tryptophan hydroxylase
2 (TPH 2) single nucleotide polymorphisms, suicide, and
alcohol-related suicide,” Psychiat. Danub., 2, 332-336 (2013).
29. A. Roy and N. Segal, “Suicidal behavior in twins: a
replication,” J. Affect Disord., 66, 71-74 (2001).
30. G. Turecki, “Suicidal behavior: is there a genetic
predisposition,” Bipolar Disord., 3, 335-349 (2001).
31. R. Clayden, A. Zaruk, D. Meyre, et al., “The association of
attempted suicide with genetic variants in the SLC6A4 and
TPH genes depends on the definition of suicidal behavior: a
systematic review and meta-analysis,” Transl. Psychiat., 2, 166
(2012).
32. V. Willour, P. Zandi, J. Badner, et al., “Attempted suicide in
bipolar disorder pedigrees: evidence for linkage to 2p12,” Biol.
Psychiat., 61, 725-727 (2007).
33. A. Suda, C. Kawanishi, I. Kishida, et al, “Dopamine D2
receptor gene polymorphisms are associated with suicide
attempt in the Japanese population,” Neuropsychobiology, 59,
130-134 (2009).
34. S. Shindo and N. Yoshioka, “Polymorphisms of the
cholecystokinin gene promoter region in suicide victims in
Japan,” Foren. Sci. Int., 150, 85-90 (2005).
35. J. Roggenbach, B. Muller-Oerlinghausen, and L. Franke,
“Suicidality, impulsivity and aggression — is there a link
to 5HIAA concentration in the cerebrospinal fluid?” Psychiat.
Res., 113, 193-206 (2002).
36. J. Mann, P. McBride, G. Anderson, and T. Mieczkowski,
“Platelet and whole blood serotonin content in depressed
inpat ien ts : Corre la t ions wi th acute and l i fe - t ime
psychopathology,” Biol. Psychiat., 32, 243-257 (1992).
37. L. Almeida-Montes, V. Valles-Sanchez, J. Moreno-Aguilar,
et al., “Relation of serum cholesterol, lipid, serotonin and
tryptophan levels to severity of depression and to suicide
attempts,” J. Psychiat. Neurosci., 25, 371-377 (2000).
38. D. Lester, “The concentration of neurotransmitter metabolites
in the cerebrospinal fluid of suicidal individuals: A meta-
analysis,” Pharmacopsychiatry, 28, 45-50 (1995).
39. S. Tyano, G. Zalsman, H. Ofek, et al., “Plasma serotonin
levels and suicidal behavior in adolescents ,” Eur.
Neuropsychopharmacol., 16, 49-57 (2006).
40. G. Pandey and Y. Dwivedi, Peripheral Biomarkers for Suicide.
The Neurobiological Basis of Suicide, CRC Press, Boca Raton
(FL) (2012).
41. C. Stockmeier, L. Shapiro, G. Dilley, et al., “Increase in
serotonin-1A autoreceptors in the midbrain of suicide victims
with major depression – postmortem evidence for decreased
serotonin activity,” J. Neurosci., 18, 7394-7401 (1998).
42. S. Lowther, F. DePaermentier, S. Cheetham, et al., “5-HT1A
receptor binding sites in post-mortem brain samples from
depressed suicides and controls,” J. Affect Disord., 42, 199-
207 (1997).
43. R. Davidson, K. Putnam, and C. Larson, “Dysfunction in the
neural circuitry of emotion regulation – a possible prelude to
violence,” Science, 289, 591-594 (2000).
44. D. Purselle and C. Nemeroff, “Serotonin transporter:
a potential substrate in the biology of suicide,” Neuro
psychopharmacology, 28, 613-619 (2003).
45. M. Padurariu, R. Prepelita, A. Ciobica, et al., “Short review
on the aggressive behavior: genetical, biological aspects and
oxytocin relevance,” Int. Lett. Natur. Sci., 52, 43-53 (2016).
46. J . Mann, “Role of the serotonergic system in the
pathogenesis of major depression and suicidal behavior,”
Neuropsychopharmacology, 21, S99-S105 (1999).
47. M. Nock, G. Borges, E. Bromet, et al., “Suicide and suicidal
behavior,” Epidem. Rev., 30, 133-154 (2008).
48. G. Zarkin, J. Bray, A. Aldridge, et al., “The effect of alcohol
treatment on social costs of alcohol dependence: results from
the COMBINE study,” Med. Care, 48, 396-401 (2010).
49. H. C. Wilcox, K. R. Conner, and E. D. Caine, “Association
of alcohol and drug use disorders and completed suicide: an
empirical review of cohort studies,” Drug. Alcohol. Depend.,
7, Suppl. 76, S11-S19 (2004).
50. M. Virkkunen and M. Linnoila, “Brain serotonin, type II
alcoholism and impulsive violence,” J. Study Alcohol. Suppl.,
Sept., 163-169 (1993).
51. G. N. Pandey, “Biological basis of suicide and suicidal
behavior,” Bipolar Disord., 15, No. 5, 524-541 (2013).
52. D. Grossman and G. DeGaetano, Stop Teaching Our Kids to
Kill, Crown Publ., New York (1999).
53. S. Fudalej, M. Ilgen, M. Fudalej, et al., “Clinical and genetic
risk factors for suicide under the influence of alcohol in a
polish sample”, Alcogol and Alcohol., 44, No. 5, 437-442
(2009).
54. A. J. Guastella, P. B. Ward, I. B. Hickie, et al., “A single dose
of oxytocin nasal spray improves higher-order social cognition
in schizophrenia,” Schizophr. Res., 168, No. 3, 628-633 (2015).
55. A. Clarici, S. Pellizzoni, S. Guaschino, et al., “Intranasal
administration of oxytocin in postnatal depression: implications
for psychodynamic psychotherapy from a randomized double-
blind pilot study,” Front. Psychol., 6, Apr., 426 (2015).
56. E. C. Finger, J. MacKinley, M. Blair, et al., “Oxytocin for
frontotemporal dementia: a randomized dose-finding study
of safety and tolerability,” Neurology, 84, No. 2, 174-181
(2015).
57. A. J. Guastella, S. L. Einfeld, K. M. Gray, et al., “Intranasal
oxytocin improves emotion recognition for youth with autism
spectrum disorders,” Biol. Psychiat., 67, No. 7, 692-694
(2010).
58. A. Hernádi, A. Kis, O. Kanizsár, et al., “Intranasally
administered oxytocin affects how dogs (Canis familiaris)
react to the threatening approach of their owner and an
unfamiliar experimenter,” Behav. Process., 119, 1-5 (2015).
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2016.—T. 48, № 4 351
CONCEPT OF SUICIDE: NEUROPHYSIOLOGICAL/GENETIC THEORIES AND POSSIBLE OXYTOCIN RELEVANCE
59. R. Lee, C. Ferris, L. D. Van de Kar, and E. F. Coccaro,
“Cerebrospinal fluid oxytocin, life history of aggression, and
personality disorder,” Psychoneuroendocrinology, 34, No. 10,
1567-1573 (2009).
60. J. Jokinen, A. Chatzittofis, C. Hellström, et al., “Low
CSF oxytocin reflects high intent in suicide attempters,”
Psychoneuroendocrinology, 37, No. 4, 482-490 (2012).
61. E. A. Deisenhammer, S. Hofer, O. Schwitzer, et al., “Oxytocin
plasma levels in psychiatric patients with and without recent
suicide attempt,” Psychiat. Res., 200, No. 1, 59-62 (2012).
62. G. Domes, A. Lischke, C. Berger, et al., “Effects of
intranasal oxytocin on emotional face processing in women,”
Psychoneuroendocrinology, 35, 83-93 (2010).
63. A. Ciobica, I. M. Balmus, and M. Padurariu, “Is oxytocin
relevant for the affective disorders?” Acta Endocrinol., 12, 65-
71 (2016).
64. K. Bertsch, I. Schmidinger, I. Neumann, and S. Herpertz,
“Reduced plasma oxytocin levels in female patients with
borderline personality disorder,” Horm. Behav., 63, 424-429
(2013).
65. D. Gardner and R. Cowdry, “Suicidal and parasuicidal behavior
in borderline personality disorder,” Psychiat. Clin. North Am.,
8, 389-403 (1985).
66. A. Chatzittofis, P. Nordström, K. Uvnäs-Moberg, et al., “CSF
and plasma oxytocin levels in suicide attempters, the role of
childhood trauma and revictimization,” Neuroendocrinol.
Lett., 35, 213-217 (2014).
67. C. Heim, L. Young, D. Newport, et al., “Lower CSF oxytocin
concentrations in women with a history of childhood abuse,”
Mol. Psychiat., 14, 954-958 (2009).
68. D. Sasayama, K. Hattori, T. Teraishi, et al., “Negative
correlation between cerebrospinal fluid oxytocin levels and
negative symptoms of male patients with schizophrenia,”
Schizophr. Res., 139, 201-206 (2012).
69. K. Hor and M. Taylor, “Suicide and schizophrenia: a systematic
review of rates and risk factors,” J. Psychopharmacol., 24, 81-
90 (2010).
70. H. Beckmann, R. Lang, and W. Gattaz, “Vasopressin–oxytocin
in cerebrospinal fluid of schizophrenic patients and normal
controls,” Psychoneuroendocrinology, 10, 187-191 (1985).
71. D. Glovinsky, K. Kalogeras, D. Kirch, et al., “Cerebrospinal
fluid oxytocin concentration in schizophrenic patients does not
differ from control subjects and is not changed by neuroleptic
medication,” Schizophr. Res., 11, 273-276 (1994).
72. A. Sirzen-Zelenskaya, A. Gonzalez-Iglesias, J. Boutet
de Monvel, et al., “Prolactin induces a hyperpolarising
current in rat paraventricular oxytocinergic neurons,” J.
Neuroendocrinol., 23, 883-893 (2011).
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