Assessments

The CAARMS interview and The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and part of the Structured Clinical Interview for DSM-IV Axis II Disorders (SCID-II) (29, 30) were used to diagnostically assess all UHR individuals. Level of general psychiatric symptoms was measured with the Brief Psychiatric Rating Scale Expanded Version (BPRS) (31), the level of negative symptoms was measured with the Scale for the Assessment of Negative Symptoms (SANS) (32), and the level of depressive symptoms was measured with the Montgomey-Åsberg Depression Rating Scale (MADRS) (33). Inter-rater reliability was assessed using intra-class correlations for the outcome measure SANS, BPRS, and MADRS in 12 interviews (ICC ratings from.96 to.99).

The third version of the Danish Weschler Adult Intelligence Scale (WAIS-III) (34) provided estimates of current level of intelligence. Cognitive functions were assessed using selected tests from the Brief Assessment of Cognition in Schizophrenia battery (BACS) (35): list-learning, digit sequencing, verbal fluency, and symbol coding, as well as tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) (36): Stockings of Cambridge (SOC Problems solved in minimum moves) and Intra-extradimensional set shifting test (IED Total errors adjusted, lower is better). For a detailed overview on cognitive domains and tests, see Supplementary Table S1.