Cross-Cutting Symptom Domains Predict Functioning in Psychotic Disorders

ABSTRACT

Objective: Previous research shows elevated disability in psychotic disorders. However, co-occurring symptomatology has been increasingly highlighted as predictive of clinical outcomes in the psychotic spectrum. The current study investigates how both psychotic and nonpsychotic symptom domains predict functioning across psychotic disorders.

Methods: Outpatients (N = 128) with psychotic spectrum diagnoses participated in the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5) Field Trials at the Centre for Addiction and Mental Health in Toronto, Canada, in 2011, including the repeated administration of “cross-cutting” brief screening measures that assessed internalizing (eg, anxiety, depression), substance use (eg, alcohol, psychoactive drug use), and psychotic symptoms. Level of functioning was also assessed by self-report and clinician-rated World Health Organization Disability Assessment Schedule 2.0 (WHO-DAS-II). The relation between symptom domains and disability was examined concurrently and prospectively via hierarchical regression.

Results: Psychosis was strongly linked to self-reported disability when considered in isolation (β = 0.22, P < .001; R² = 0.11). However, when all 3 symptom domains were included in analyses, internalizing symptoms were the strongest concurrent (β = 0.31, P < .001; R² = 0.17) and prospective (β = 0.29, P < .001; R² = 0.15) predictor of disability. In the concurrent model, an interaction between internalizing and substance use emerged, wherein high internalizing symptoms were particularly detrimental in persons with high levels of substance use (β = 0.08, P < .05; R² = 0.014). Results were similar for clinician-rated WHO-DAS-II.

Conclusions: This research supports the potential clinical utility of rapid screening tools available in the newest psychiatric diagnostic manual. The internalizing symptom domain was the strongest predictor of functional outcome for outpatients with psychotic disorders. The results highlight the relevance of a broad range of symptoms, including those that fall outside the primary psychiatric concern, in recovery-oriented clinical work in psychosis.