Impact of Childhood Trauma Exposure on Social Functioning in Schizophrenia Patients – Role of Plasma Oxytocin as a Biomarker

Schizophrenia is a chronic and severe psychotic illness that accompanied with declination of social functioning. Social cognition and negative symptoms are accounted for substantial of the variance in the real-world social functioning. Despite growing evidence of improvement by antipsychotics treatment, social deficits remain a clinical obstacle for schizophrenic patients.Childhood trauma is one of the main risk factors for mental disorders, including schizophrenia. Alterations in mentalizing skills are hallmark features of schizophrenia, and also are evident in individuals exposed to childhood trauma. Furthermore, childhood trauma is associated with impaired working memory, executive function, verbal learning, and attention in schizophrenia patients. In these patients, higher levels of childhood trauma were correlated with higher levels of attenuated positive symptoms, general symptoms, and depressive symptoms; lower levels of global functioning; and poorer cognitive performance in visual episodic memory end executive functions.As a consequence of experiencing childhood trauma, disruption in regulation of oxytocin has been demonstrated. Oxytocin facilitates the social bonding, typically engages in prosocial behaviors, and promotes trust between individuals. In addition, oxytocin also involves in the regulation of the response to stress. Low plasma oxytocin level is also linked to a history of childhood trauma in schizophrenia patients. Oxytocin system is proposed as a candidate for pathophysiology and novel treatment strategy for schizophrenia. Lower oxytocin level was found in patients with schizophrenia than in healthy controls and the level of oxytocin was negatively correlated with the severity of symptomatology of schizophrenia, particularly negative symptoms and cognitive function. Noteworthy, intranasal supplement of oxytocin showed improvement in thecognitive function as well as social cognition and social skills of schizophrenia patients. Less is known about the theoretical frameworks to explain the mechanism leading from childhood trauma to later schizophrenia, as well as how and to what extent oxytocin plays its role.In this study, we aimed to investigate the relationship between childhood trauma and social functioning in schizophrenia patients. Learned from previous studies, this study is aiming to examine the role of oxytocin, in linking childhood trauma tosocial dysfunction of schizophrenia patients. Childhood trauma may disrupt the regulation of oxytocin, decreased in oxytocin may correlated with worsened social functioning. We hypothesized a theoretical framework that may explain the mechanism underlying childhood trauma leading to later social dysfunction in schizophrenia has been postulated as follows:(1) Severity of childhood trauma is correlates with severity of social dysfunction among schizophrenia patients. Schizophrenia patients who experienced childhood trauma have more severe social dysfunction than schizophrenia patients without childhood trauma.(2) Severity of childhood trauma is inversely correlating with plasma oxytocin level and oxytocin receptors among schizophrenia patients. Schizophrenia patients who experienced childhood trauma have lower plasma oxytocin level and oxytocin receptors than schizophrenia patients without childhood trauma.(3) Severity of social dysfunction is inversely correlating with plasma oxytocin level and oxytocin receptors among schizophrenia patients. Schizophrenia patients who have more severe social dysfunction have lower plasma oxytocinlevel and oxytocin receptors than schizophrenia patients who have less severe social dysfunction.