Comorbidity between patterns of substance use dependence and psychiatric syndromes

Background: Comorbidity of dependence on single and multiple drugs with psy chiatric syndromes was examined in national samples from the National House hold Survey on Drug Abuse (NHSDA). Methods: Subjects are adults from the 19 94, 1995 and 1996 NHSDA surveys. Proxy measures of drug dependence in the l ast year were constructed from five dependence symptoms that approximated D SM-IV criteria. Measures of patterns of concurrent dependence on cigarettes , alcohol and illicit drugs were constructed. Fallible indicators of a majo r depressive episode and any anxiety disorder (generalized anxiety disorder , agoraphobia and panic attack) were based on scales measuring symptoms dur ing the last: year. Comorbidity was estimated by adjusted odds ratios. Resu lts: Probable drug dependent individuals have higher rates of psychiatric s yndromes. Rates of psychiatric syndromes were similar for those uniquely de pendent on alcohol, cigarettes or illicit drugs (adjusted odds ratios appro ximate to 2.0). Rates almost doubled for those dependent on both an illicit and a licit drug. Conclusions: Individuals uniquely dependent on a single drug class experience similar rates of psychiatric morbidity. All those dep endent on illicit drugs experience higher rates of psychiatric syndromes. T his reflects the additive association of dependence on legal and illegal dr ugs with psychiatric disorders and the increased rates of dependence on a l egal drug among those dependent on an illicit drug. Individuals with multip le dependencies on legal and illegal drugs have the highest need for mental health services. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.