Clinical practice guideline on pharmacological and psychological management of adult patients with schizophrenia spectrum disorders and a comorbid substance use

Although correct diagnosis and management of patients with schizophrenia and a comorbid substance use disorder (SUD) would determine a decrease in morbidity and mortality in these patients, development of efficient therapeutic strategies is still pending. We present recommendations on the pharmacological and psychological management of these patients following the 'PICO' structure (Patient-Intervention-Comparison-Outcomes). Evaluation of the quality of studies and summary of the evidence for each question was performed following the recommendations of the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) working group. Our results suggest: 1) In patients with schizophrenia and cannabis use disorder, it is not possible to recommend one antipsychotic drug over another (between olanzapine, risperidone or haloperidol) for improving psychotic symptoms, reducing cannabis use, or improving pragmatic variables (weak recommendation). Clozapine cannot be recommended to reduce cannabis use (weak recommendation). 2) In patients with schizophrenia and cocaine use disorder we recommend haloperidol over olanzapine to reduce craving (moderate recommendation), and olanzapine over haloperidol to improve motor side effects in these patients (moderate recommendation). 3) In patients with schizophrenia and alcohol use disorder while naltrexone is recommended to reduce alcohol use (in terms of reducing alcohol craving) (weak recommendation), there is insufficient evidence to make any recommendation on the use of adjuvant acamprosate (weak recommendation). 4) In patients with schizophrenia and nicotine use disorder, adjuvant bupropion and varenicline are recommended for reducing nicotine use and nicotine abstinence (strong/moderate recommendation). 5) In patients with schizophrenia and polydrug use disorder, second-generation over first-generation antipsychotic drugs and olanzapine over other second-generation antipsychotics are recommended to improve psychotic symptoms (moderate/weak recommendation).