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08-06-2010 | Mental health | Article

Stress-reactivity is intermediary phenotype for psychosis


Free abstract

MedWire News: The siblings of patients with psychosis and severe positive symptoms tend to show increased reactivity to stress compared with the siblings of psychosis patients with mild positive symptoms, study results show.

Inez Myin-Germeys (Maastricht University, The Netherlands) and fellow study authors say that stress-reactivity could “reflect a specific mechanism underlying the development of positive symptoms.”

The search for causal mechanisms in schizophrenia has led to an increased interest in the study of so-called “intermediary phenotypes,” the researchers explain in the journal Acta Psychiatrica Scandinavica.

Studies have shown that individuals with an increased liability for psychosis are more reactive to environmental stressors, thus identifying stress as a potential intermediary phenotype candidate.

To investigate, the researchers recruited 40 patients with a DSM-IV-defined non-affective psychotic disorder and 47 of their mentally healthy siblings.

The experience sampling method (ESM) was used to measure the emotional reaction to stress in the flow of daily life.

Regression analysis revealed a significant correlation between stress-reactivity in the siblings and stress-reactivity in patients. Accordingly, siblings of patients with high stress-reactivity were more reactive to stress in daily life themselves than were the siblings of patients with lower stress-reactivity.

Myin-Germeys and colleagues say this finding represents “familial clustering of stress-reactivity,” probably due to genetic or environmental factor or interaction of the two.

There was also a significant interaction between stress-reactivity in the siblings and positive symptoms scores in patients – such that siblings of patients with high or intermediate positive symptoms scores showed high stress-reactivity compared with patients with low scores on positive symptoms.

Myin-Germeys and colleagues call for interventions specifically aimed at reducing stress in the social environment of the patient.

“Self-relaxation and distraction techniques are often incorporated within the cognitive behavioral therapy (CBT) for psychosis protocol, thus adapting CBT to remediate stress-sensitivity,” they comment.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Andrew Czyzewski

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