SYMPOSIA

Abstracts of the Invited Speakers
Effects of oxytocin on social behaviour
Nuray Atasoy
Zonguldak Karaelmas University, Faculty of Medicine, Psychiatry Department, Zonguldak, Turkey
E-mail: nurayulus@yahoo.com
Oxytocin (OXT) is traditionally viewed as a female hormone that is primarily associated with labor and it has a very special affect on
mothering. In mothers it increases their attachment to their infant, promoting the feeling of love, and makes her infant more valuable
to her. Oxytocin has been called the love and bonding hormone. Furthermore, oxytocin mediates attachment behavior over the course
of development, with lower urinary concentrations of oxytocin found in maltreated children and in adult males with a history of early
separation. Psychologically, oxytocin promotes a feeling of well being and tranquility. It also suppresses the fear that would normally
cause a mother to back off from a threat. In humans, based on the animal literature, it has been postulated that beyond these peripheral
actions, central OXT modulates cognition in the context of social interactions, thus promoting positive sociality.
In particular, recent experiments have shown that OXT promotes trusting behavior, enhances facial emotion recognition and memory
for positive social information, reduces social stress, improves social cognition in socially impaired individuals with autism, and alters
dysfunctional cognition in social phobia.
Functional imaging studies have just begun to elucidate the underlying neural correlates of these pro-social effects. A number of studies
have provided evidence that the amygdala might be a key structure for the mediation of the social cognitive effects of OXT. Several studies
have shown that a single dose of OXT reduced amygdala reactivity to pictures of aversive scenes and faces with negative valence.
While studies of oxytocin and monogamous behavior in humans have not been conducted to date, one study found that in co-habiting
couples, greater partner support is associated with higher plasma oxytocin in both men and women before and after a period of warm
partner contact.
The OXT system is a sexual dimorphic system. For example, OXT plasma levels tend to be higher in females and synthesis, as well as OXT
receptor affinity, appears to be modulated by gonadal steroids such as estradiol and progesterone. It has been shown, in a study on
prairie voles, that female parenting behavior is more dependent on OXT, whereas male parenting behavior is associated with vasopressin.
Another study demonstrated that aggression is associated with OXT in females, but not in males. However, the hypothesis of homology
between paternal and maternal behavior has not yet been adequately tested and it is possible that different neuroendocrine circuits could
lead to the same behavior in males and females. Future studies should include both sexes to determine a possible sexual dimorphism in
the neural effects of OXT, considering gonadal steroids and OXT receptor affinity.
Key words: Oxytocin, social behaviour
Bulletin of Clinical Psychopharmacology 2011;21(Suppl. 2):S76
Thyroid hormones and psychiatric disorders
Tayfun Turan
Department of Psychiatry, Erciyes University, Kayseri, Turkey
E-mail: mtturan@erciyes.edu.tr
The role of the hypothalamic-pituitary-thyroid (HPT) axis in psychiatric symptoms and disorders has been stressed in many studies.
Secretion of thyroid hormones is controlled by this axis. Hypothalamic thyrotropin releasing hormone (TRH) stimulates pituitary
thytrotropin-stimulating hormone (TSH) and the latter controls the secretion of thyroid hormones. Serum thyroid hormones regulate the
HPT axis by a negative feedback system. The main secretion of the thyroid gland is thyroxine (T4). T4 is converted into triiodothyronine (T3)
in various tissues, especially in brain, by enzymes called “deiodinases”. Transthyretin, a hormone transporter, transports T4 into the brain (1).
Thyroid hormones play a critical role in the developing and functioning of the brain (2). In this regard, it is suggested that interactions
between thyroid hormones and neurotransmitter systems, especially serotonin (5-HT), norepinephrine (NE) and acetyl choline (Ach),
probably contribute to the regulation of mood and behaviour (1). T3 enhances the effects of NE, 5-HT and γ-aminobutyric acid, which are
thought to be involved in the etiology of some psychiatric conditions (3).
In the literature there are many case reports and studies indicating probable relationships between clinical or subclinical thyroid diseases
and psychiatric disorders. So far, many cases have been reported of hypothyrodism or hyperthyroidism associated with psychiatric
disorders, including mania, depression, schizophreniform psychosis, paranoid psychosis, cognitive disturbances, delirium and anxiety
S76 Bulletin of Clinical Psychopharmacology, Vol: 21, Supplement: 2, 2011 - www.psikofarmakoloji.org