Preliminary Evidence on the Efficacy and Tolerability of Quetiapine in Dual Disorders: A Prospective, Multicentric, Real-World Study

Background: Dual disorders (DDs) describe the coexistence of substance use disorder (SUD) and another mental health condition, commonly within psychotic and affective categories. These conditions represent a significant challenge in clinical management due to their bidirectional interactions and complexity. This study aims to evaluate the efficacy and safety of quetiapine, a second-generation antipsychotic, in patients with schizophrenia spectrum disorders and comorbid substance use disorders. Methods: A total of 28 participants with schizophrenia spectrum disorder and comorbid SUD underwent psychometric evaluations at baseline (T0), one month (T1) and three months post-initiation of quetiapine treatment (T2), administered at a mean dosage of 165 mg/day. Key outcome measures included psychopathological burden (PANSS), aggressivity (MOAS), substance craving (VAS Craving), and quality of life (Q-LES-Q-SF scales). Results: Quetiapine demonstrated significant reductions in psychopathological symptoms, with decreased PANSS total scores (p < 0.001). Positive symptoms (p < 0.001), negative symptoms (p = 0.002), substance craving (p = 0.001), and aggressivity (p = 0.006) also showed notable reductions. Quality of life significantly improved across Q-LES-Q-SF scores (p < 0.001). Quetiapine was well-tolerated, with no dropouts related to drug-induced side effects. Conclusions: This study provides preliminary evidence supporting the efficacy and safety of quetiapine in individuals with dual disorders. Improvements in psychopathology, substance craving, and quality of life underscore the importance of integrating tailored and comprehensive treatment strategies to address the multifaceted challenges of this challenging population.