Substance use and psychiatric disorders in patients referred to consultation-liaison psychiatry within a regional general hospital

Abstract

Abstract Little is known about clinically important differences between patients depending on the number of comorbid psychiatric disorders, or the presence or absence of a substance use disorder (SUD) comorbidity. This study investigated for differences in psychosocial disadvantage, psychiatric disorders, and health service amongst 194 general hospital patients referred to consultation-liaison psychiatry (CLP) with no psychiatric diagnosis, single psychiatric diagnosis, multiple (non-SUD) psychiatric diagnoses, or psychiatric diagnosis plus SUD comorbidity. The results showed that SUDs were the commonest diagnostic category (34%). The SUD comorbidity group had more disadvantaged housing, were prescribed most psychoactive medications, and 20% prematurely self-discharged against medical advice. Increased SUDs were associated with reduced length of stay, men, younger age, increased investigations, and reduced private health insurance subscription. Patients with SUD comorbidity versus multiple psychiatric diagnosis had reduced odds of Adjustment Disorder, Somatic Symptom Disorder, and Insomnia Disorder. Post Traumatic Stress Disorder was the strongest predictor of multiple SUDs, followed by Cluster B personality disorders. In conclusion, SUDs have become a leading clinical focus for CLP. The presence or absence of SUDs amongst patients with multiple psychiatric disorders has important clinical implications for engagement, diagnosis, prescribing, and outpatient follow-up.