Dopaminergic mechanisms are involved in addiction but few effective drugs have been developed to treat it. Recent research has highlighted dopamine D2 receptor partial agonists, like aripiprazole, as a potential treatment for different types of substance dependence. In this study we investigate the use of both oral or long-acting injectable (LAI) aripiprazole in the treatment of dual disorders, specifically focusing on patients with psychotic disorder and comorbid substance use disorder.

Retrospective mirror-image study was conducted at an adult psychiatry inpatient unit from a tertiary care center (Ramon y Cajal University Hospital, Madrid, Spain). Patients included were those with a comorbid psychotic disorder and substance-related disorders (excluding tobacco and caffeine), according to DSM-5 criteria, who started aripiprazole in 2017. The number of psychiatric acute inpatient admissions and psychiatric emergency room visits, six months before and after aripiprazole initiation, were obtained from patients’ records. Sociodemographic factors, average length of stay, antipsychotic polypharmacy, type of substance and change on clinical global impression (GCI) scale during hospitalization were also obtained. Data was analyzed using the IBM SPSS, v21. The Wilcoxon signed-rank test was used in the analysis.

11 patients were included; 7 (63.6%) were males, the mean age was 40.37 (SD:13.23) years and the average length of stay was 11.27 (SD:7.53) days. LAI aripiprazole was prescribed in 7 (63.6%) patients (all of them receiving 400mg monthly) and oral aripiprazole was prescribed in 4 (36.4%) patients (mean daily dose= 16.25mg; SD:10.30). Antipsychotic polypharmacy was observed in 6 (54.5%) patients: 4 with quetiapine (mean daily dose=75mg; SD:61.23), 1 with clotiapine 20mg daily and 1 olanzapine 15mg daily. There were 6 (54.5%) polysubstance users and the substances used were cannabis (63.7%), alcohol (36.4%), stimulants (27.3%), opioids (9.1%), hallucinogens (9.1%) and sedative-hypnotics (9.1%).

The mean of inpatient admissions before and after aripiprazole initiation was 1.00 (SD:1.00) and 0.18 (SD:0.60) (p=0.047). The mean of emergency room visits before and after aripiprazole initiation was 1.64 (SD:1.85) and 0.36 (SD:0.67) (p=0.026). With respect to CGI scale, the severity of illness score was 5.09 (SD:0.94) and the global improvement score was 2.00 (SD:0.63) (p=0.004).

These results suggest that aripiprazole could be an effective treatment in psychotic patients with comorbid substance use disorders. However, the results should be taken with caution due to some limitations in our study: a small sample, the short period of time studied, the retrospective design and the inherent biases associated with this type of research. Preliminary investigations on the topic and the results of our study allow clinicians to be optimistic about the use of D2 receptor partial agonist in the treatment of dual disorders.