The assessment of schizotypal features over two points in time

The expression of schizotypal personality traits was assessed in mid-adolescence and again in young adulthood for three groups of offspring defined by the psychiatric diagnosis of their parents. Parental diagnoses included schizophrenic disorder (47 offspring), affective disorder (39 offspring), and 'no psychiatric disorder', or normal controls (82 offspring). Initially, schizotypal traits were assessed from video-taped semi-structured psychiatric interviews, subsequently rated by trained psychiatrists blind to the parental psychiatric status of the subjects, and/or direct clinical interviews (Schedule for Affective Disorders-Lifetime Version (SADS-L)). The second assessment was conducted by trained social workers and psychologists by means of a semi-structured interview specifically for DSM-III-R personality disorders (Personality Disorder Examination) and sections of the SDS-L where indicated. These interviewers were blind to the parental status and to previous psychiatric assessments of the offspring. The rates of stability of features or the rates of progression to axis I psychotic disorders (Schizophrenia, Schizoaffective Disorder, and Unspecified Functional Psychosis) were evaluated. Concordance of assessments over time is reported as a function of threshold for expression of traits at initial evaluation, i.e., two or more, three or more, or four or more features present. Concordance increases as the threshold for expression increases, as expected. The effect of comorbid clinical status, e.g., the coexistence of schizotypal traits and anxiety and/or depressive features on the concordance pattern, is also examined by parental diagnostic group status. The offspring of affective disorder parents exhibited higher rates of anxiety and/or depressive features at both points in time, exhibited higher concordance for anxiety and/or depressive features, and exhibited higher rates of 'transformation' of initial schizotypal features to anxiety and/or depressive features at the second assessment.