Background: Evaluation of individuals at high genetic risk of schizophrenia is a powerful method for identifying precursors of the illness.
Aims: To identify aspects of personality, psychopathology and social development that differentiate high-risk and control individuals.
Method: Adolescent and young-adult first-degree relatives (n=35) of people with schizophrenia or schizoaffective disorder and a control group (n=55) were compared on 36 measures at baseline of a longitudinal study. Measures differentiating high-risk and control participants were related to four genetic loading indices.
Results: High-risk participants older than 17 years showed more physical anhedonia, less positive involvement with peers and more problems with peers, siblings and the opposite gender. Older high-risk individuals also were less cooperative, less self-directed and less reward-dependent. Problems with peers and the opposite gender, as well as reward dependence, were related linearly to genetic loading.
Conclusions: Alterations in personality traits and social development are present in high-risk individuals, and may be markers for genetic liability toward the illness.