Psychiatric Comorbidity as a Function of Severity: DSM‐5 Alcohol Use Disorder and HiTOP Classification of Mental Disorders

Background Understanding the comorbidity of alcohol use disorder (AUD) and other psychiatric diagnoses has been a long‐standing interest of researchers and mental health professionals. Comorbidity is often examined via the diagnostic co‐occurrence of discrete, categorical diagnoses, which is incongruent with increasingly supported dimensional approaches of psychiatric classification and diagnosis, and for AUD more specifically. The present study examined associations between DSM‐5 AUD and psychiatric symptoms of other DSM‐IV and DSM‐5 disorders categorically, and dimensionally organized according to the Hierarchical Taxonomy of Psychopathology (HiTOP) spectra (e.g., Internalizing, Disinhibited Externalizing). Methods The comorbidity of AUD with other psychological disorders was examined in 2 independent nationally representative samples of past‐year drinkers via an initial examination in the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) Wave 2 and replicated in NESARC‐III. Results Analyses focusing on psychopathology symptom counts organized by spectra demonstrated that greater AUD severity was associated with a higher number of symptoms across HiTOP spectra. Traditional categorical analyses also demonstrated increasing prevalence as a monotonic function of DSM‐5 AUD severity gradients. Conclusions This study indicates that AUD and other psychiatric disorder comorbidity implies increased presence of multiple forms of psychopathology with a corresponding increased number of symptoms across hierarchical spectra. Greater AUD severity increases the likelihood of other psychopathology and, when present, “more severe” presentations. That is, on average, a given disorder (e.g., depression) is more severe when copresenting with an AUD, and increases in severity along with the AUD. This study examined the association between DSM‐5 AUD and symptoms of other psychiatric disorders, organized dimensionally according to the Hierarchical Taxonomy of Psychopathology spectra (e.g., Internalizing, Disinhibited Externalizing). Samples were from two large epidemiological samples. Greater AUD severity was associated with a higher number of symptoms across all spectra. Specifically, comorbidity of increasingly severe AUD implied increased presence of multiple forms of psychopathology of increasing severity. This pattern was most pronounced for Externalizing spectra and least pronounced for Detachment.