Clinical characteristics of adolescents later hospitalized for schizophrenia

Intellectual and behavioral abnormalities, non-psychotic psychiatric disorders, and drug abuse are sometimes present in adolescents who later develop schizophrenia. We followed a population-based cohort of adolescents with baseline assessments of intellectual and behavioral functioning, non-psychotic psychiatric disorders and drug abuse, and ascertained future hospitalization for schizophrenia. Results of the medical and mental health assessments on 16- to 17-year-old male adolescents screened by the Israeli Draft Board, were cross-linked with the National Psychiatric Hospitalization Case Registry, which contains data on all psychiatric hospitalizations in the country. Male adolescents who were later hospitalized for schizophrenia had significantly poorer test scores on all measures in comparison with adolescents not reported to the Psychiatric Registry, the magnitude of the differences was 0.3-0.5 standard deviation (SD). Adolescents (1.03%) of assigned a non-psychotic psychiatric diagnosis, compared to of the adolescents without any psychiatric diagnosis (0.23%), were later hospitalized for schizophrenia. Patients with schizophrenia (26.8%), compared to only 7.4% in the general population of adolescents, had been assigned a non-psychotic psychiatric diagnosis in adolescence (overall OR = 4.5, 95% CI = 3.6-5.6), ranging from OR = 21.5, (95% CI = 12.6-36.6) for schizophrenia-spectrum personality disorders to OR = 3.6 (95% CI = 2.1-6.2) for neurosis. The prevalence of self-reported drug abuse was higher in adolescents later hospitalized for schizophrenia (12.4%), compared to the prevalence of drug abuse in adolescents not later hospitalized (5.9%); adjusted RR = 2.033, 95% CI = 1.322-3.126. These results reflect the relatively common finding of impaired intellectual and behavioral functioning, the presence of non-psychotic psychiatric disorders, and drug abuse, in adolescents later hospitalized for schizophrenia, together with the relatively low power of these disorders in predicting schizophrenia.