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.