Social defeat links past trauma to current psychosis

By Eleanor McDermid, Senior medwireNews Reporter

The feeling of social defeat may be responsible for the link between childhood trauma and psychosis, research suggests.

“The present study underscores the importance of incorporating trauma history in standard mental health care, contrary to current medical practice,” say study authors Ruud van Winkel (Maastricht University Medical Centre, the Netherlands) and team.

Social defeat refers to the feelings of outsider status and reduced social value. These can arise as a consequence of several known risk factors for psychosis, including migration and various forms of abuse.

The researchers assessed 10 symptoms of self-devaluation, feelings of worthlessness, and hopelessness for the future – chosen to represent social defeat – in 6357 participants of the second Netherlands Mental Health Survey and Incidence Study. In factor analysis, seven of these items loaded on a single factor, and were used in a social defeat scale with a score of 0–7.

In all, 0.7% of participants had a DSM-IV psychotic disorder (schizophrenia or schizophreniform disorder) and 6.0% had had at least one lifetime psychotic experience. Social defeat scores were increased in these two groups, at 4.3 and 2.0, respectively, versus 0.8 in participants without psychotic experiences.

As anticipated, childhood trauma was associated with psychosis, and it was also associated with social defeat and affective dysregulation. In mediation models, both affective dysregulation and social defeat linked childhood trauma to psychosis, but the link between childhood trauma and affective dysregulation was entirely mediated by social defeat.

This suggests a developmental pathway, with childhood trauma leading to feelings of social defeat, resulting in affective dysregulation and psychotic symptoms, say van Winkel et al in Acta Psychiatrica Scandinavica.

Of note, both mediation models the team used showed that social defeat and affective dysregulation jointly mediated the link between childhood trauma and lifetime psychotic symptoms, whereas social defeat was solely responsible for the link with psychotic disorders.

The researchers attribute this to the broad definition of lifetime psychotic experiences, which includes psychosis within affective disorders, thus explaining the prominent role of social defeat in the “more narrow outcome” of psychotic disorders.

Overall, they conclude their study supports the theory “that experiences that lead individuals to feel rejected by their immediate social environment (i.e. their peers or direct family) may increase risk for psychosis by causing feelings of outsider status and not fitting in.”

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