Association between global functioning at first schizophrenia diagnosis and treatment resistance

Aim: Several factors such as age, gender, urbanicity and clinical treatment setting have been associated with treatment-resistant schizophrenia (TRS). We examined the association between the Global Assessment of Functioning (social Functioning [GAF-F]) score at first schizophrenia diagnosis and TRS and explored whether level of functioning could partially explain the known associations. Methods: A nationwide population-based cohort study among individuals, who had a GAF-F score at first schizophrenia diagnosis. We used adjusted Cox regression analysis to calculate hazard ratios (HRs). Results: Among 3252 individuals, severe functional impairment (GAF-F <= 30) was associated with TRS within 2 years after diagnosis (adjusted HR = 1.38 [95% confidence interval: 1.03-1.87). GAF-F had virtually no impact on the associations between investigated known risk factors and TRS. Conclusions: GAF-F was independently associated with TRS. Consideration of a global functioning score may help clinicians to detect treatment resistance earlier among individuals with schizophrenia.