Velthorst E, Meijer C,
Schizophr. Res. 2012 Jul;138(2-3):290-4
BACKGROUND: Social anhedonia (SA) and withdrawal are clinically relevant phenomena in schizophrenia. To examine the nature of the overlap between SA, withdrawal and positive symptoms, we investigated whether the co-occurrence of these phenotypes is more prominent in siblings of patients with a psychotic disorder compared to healthy controls, and if this association is independent of the amount of distress caused by psychotic experiences (PEs).
METHOD: Data were derived from 646 unaffected siblings and 326 healthy controls who were included in the Dutch Genetic Risk and Outcome in Psychosis (GROUP) study. PEs were assessed with the Community Assessment of Psychic Experiences and the Structured Interview for Schizotypy-Revised was used to examine social anhedonia and withdrawal.
RESULTS: Our results show relatively small but significant cross-sectional associations between SA, withdrawal and PEs in unaffected siblings and none in the control group, irrespective of the level of distress caused by PEs.
CONCLUSIONS: The findings of the present study suggest that the overlap between SA, withdrawal and psychotic symptoms often reported in schizophrenia patients, may at least partly reflect a shared genetic vulnerability, instead of merely being either a state marker of – or reaction to – acute psychotic symptoms.