Childhood premorbid adjustment as a marker for 20-year impairments in schizophrenia spectrum disorder: results from the OPUS study.

Growing evidence reveals relative stability in long-term clinical and functional outcomes of schizophrenia spectrum disorders (SSD), and links poor premorbid adjustment (PA) to worse prognoses. This study investigated associations between PA across developmental stages and long-term outcomes. Data on 496 participants (age 26.8 ± 6.5, male 58.5%) from the Danish randomised OPUS I trial were used (January 1998-December 2000; NCT00157313). Participants, with a first diagnosis within SSD, were recruited from outpatient and inpatient mental health services in Denmark and followed up for twenty years (retention = 29.0%). PA was assessed retrospectively at baseline using the Premorbid Adjustment Scale. Academic and social domain scores in childhood, and their subsequent changes in early and late adolescence, were used. Mixed models examined their effects on social functioning (Global Assessment of Functioning) and negative symptoms (Scales for the Assessment of Negative Symptoms). Low social functioning was associated with worse Social (β[95%CI] = 6.46 [0.54, 12.38], P ≤ 0.033) and Academic (9.40 [3.35, 15.44]; P ≤ 0.002) PA in childhood. Severe negative symptoms were associated with impaired Social PA in childhood (1.23 [0.73, 1.73], P ≤ 0.001), deterioration of Social PA in early adolescence (1.64 [0.93, 2.35], P ≤ 0.001), and declined Academic PA in late adolescence (0.77 [0.14, 1.39], P ≤ 0.016). Poor PA in childhood and PA decline during adolescence are related to Severer negative symptoms and lower social functioning 20 years after SSD onset. Our findings suggest that early signs may emerge in childhood, alongside age-dependent vulnerability-accumulation processes, when developing SSD. Support for maladjusting individuals during development is necessary to mitigate long-term impairments.