Parsing the effects of comorbid adult ADHD and substance misuse on affective lability in bipolar disorder

Introduction: Attentional deficits, substance misuse, and affective lability are all common features among adults with bipolar disorder, but little research has attempted to parse their inter-relationships. Methods: Using standardized scales and semi-structured interviews, we evaluated adult ADHD features and affective lability in 113 dually-diagnosed mood/substance use disorder inpatients (mean age 32.6 years, 63% female) drawn from one private suburban academically affiliated inpatient treatment program. Results: 24% of bipolar subjects had above-threshold ADHD screens. Affective Lability Scale (ALS) total and subscores were significantly associated with ADHD scores (univariate r's ranging from 0.38–0.63). ALS total and most subscale scores were significantly higher among bipolar subjects having above- (versus below-) threshold ADHD ratings. Linear regressions to predict affective lability revealed significant partial correlations between bipolar diagnoses and ALS total, depression, elation, and anger subscores, while controlling for significant effects from ADHD comorbidity. Inclusion of current substances of abuse did not change goodness-of-fit. Limitations: Subjects were drawn from a single private institution, potentially limiting generalizability. Conclusions: Comorbid ADHD appears to moderate multiple domains of affective lability in bipolar disorder inpatients, independent of current substance misuse.