Premorbid Characteristics as Predictors of Early Onset Versus Adult Onset in Patients With a First Episode of Psychosis.

To study the differences in early-life characteristics between patients with an early onset of psychotic disorders (EOP, aged < 18 years) versus adult onset of psychotic disorders (AOP, aged ≥ 18 years) and to identify predictors of earlier onset. 278 patients with a first episode of psychosis between the ages of 7 and 35 years were recruited as part of a multicenter prospective longitudinal study conducted in Spain between January 1, 2009, and December 31, 2011, with diagnoses made for AOP using the Structured Clinical Interview for Axis I Disorders (SCID-I) and for EOP using the Schedule for Affective Disorders and Schizophrenia for School-Aged Children (K-SADS). Early-stage factors such as prenatal, perinatal, and other premorbid factors were registered and compared between EOP and AOP patients. To analyze the association between baseline variables and outcome, univariate and multivariate logistic regression models were used, and the association or odds ratios (ORs) for significant risk factors were calculated. 224 patients with AOP (mean ± SD age = 25.6 ± 5.0 years; 65.6% male) and 54 patients with EOP (16.1 ± 1.7 years; 68.5% male) were included. Univariate analysis revealed significant differences between the groups. Specifically, compared to AOP subjects, EOP patients had more frequent obstetric complications (OCs) ( < .001), birth weight < 2.500 g ( < .028), a background of any personal psychiatric disorder ( < .001), a previous diagnosis of attention-deficit/hyperactivity disorder ( = .001), and premorbid IQ < 85 ( < .001). In the multivariate model, only OCs (OR = 5.44), personal psychiatric background (OR = 4.05), and IQ < 85 (OR = 3.96) predicted an onset of the first episode of psychosis before age 18 years. Premorbid factors such as OCs, personal psychiatric background, and IQ < 85 could help predict which patients are more likely to have an early onset of psychosis. Awareness of these factors could help clinicians work to prevent the early transition to psychosis in children and adolescents.