(PS1-13) Differential Associations Between Substance Use Disorders and Psychiatric Comorbidities in a Large Clinical Sample

Substance use disorders (SUDs) commonly co-occur with psychiatric illnesses, and research indicates that the prevalence and type of comorbidities can vary by substance. Few studies have directly compared the distribution of psychiatric comorbidities across different types of SUDs within large, real-world treatment samples. This analysis aims to examine whether certain SUDs are differentially associated with specific mental health conditions in a large cohort of patients receiving treatment for substance use.
Data collected from 5 SUD treatment clinics from 1990-2024 (N = 6209) were analyzed (61.1% male; mean age = 40.5, SD = 27.6). Patients were categorized into SUD groups based on type of substance(s) used from their primary ICD-10 diagnoses. Psychiatric comorbidities were also classified using ICD-10 mental health diagnoses.
The association between SUD groups and mental health diagnoses was examined using Pearson’s Chi-Square Test to assess whether significant differences existed between groups. There was a highly significant overall association (p < .001), indicating that mental health diagnoses significantly differed across SUD groups.
Post-hoc pairwise chi-square tests with Bonferroni correction found that the polysubstance group was most likely to have depressive and bipolar disorders (p < .001) compared to all other SUD groups. The polysubstance group was also significantly more likely to have an anxiety disorder than alcohol, cannabis, and opioid groups (p < .001). The cannabis group was more likely than alcohol or opioid groups to have a psychotic disorder (p < .001). The stimulant group had higher rates of bipolar disorders than alcohol (p < .001) or opioid (p=.001) groups and was also associated with psychotic disorders (p=.006). The sedative group had higher rates of anxiety disorders than the alcohol group (p < .001).
These findings highlight the differential associations between specific SUDs and psychiatric comorbidities and may assist clinicians in better understanding the relationship between symptoms and substance use to guide treatment. For example, considering the strong association between polysubstance use disorder and mood disorders, treatment approaches should prioritize mood stabilization strategies. Further, given the link between cannabis use and psychotic disorders, reducing cannabis use may help mitigate psychotic symptom severity. These results emphasize the importance of integrating mental health screening in SUD care. This integration is vital for the development of personalized targeted interventions that improve overall patient outcomes. Future research should examine whether these associations persist after controlling for demographic factors, as these variables may influence substance use patterns and psychiatric comorbidities.