Coping drinking motives, neural functional coupling during emotion processing, and alcohol use in young adults with bipolar disorder

Abstract

Background: Rates of alcohol use disorders in individuals with bipolar disorder are 3 to 5 times greater than in the general population and exceed rates of alcohol use disorders reported in other affective and anxiety disorders. Despite this high rate of comorbidity, our understanding of the psychosocial and neural mechanisms that underlie the initiation of alcohol misuse in young adults with bipolar disorder remains limited. Prior work suggests that individuals with bipolar disorder may misuse alcohol as a coping mechanism, yet the neural correlates of coping drinking motives and associated alcohol use have not been previously investigated in this population.

Methods: Forty-eight young adults (22 bipolar disorder type I, 26 typically developing; 71% women; average age ± standard deviation = 22 ± 2 years) completed the Drinking Motives and Daily Drinking Questionnaires, and a Continuous Performance Functional magnetic resonance imaging (fMRI) Task with Emotional and Neutral Distracters. We calculated the relative difference in anterior cingulate cortex (ACC) functional coupling with the anterior insula and amygdala in response to emotional distracters compared with neutral stimuli and investigated the relations with coping drinking motives and alcohol use.

Results: Across all participants, coping drinking motives were associated with greater quantity of recent alcohol use. In individuals with bipolar disorder, greater ACC-anterior insula functional coupling was associated with greater coping drinking motives, and greater quantity and frequency of recent alcohol use. The relative difference in ACC-anterior insula functional coupling was not associated with coping drinking motives or alcohol use in the typically developing group. Greater ACC-anterior insula functional coupling in individuals with bipolar disorder was also associated with greater anxiety symptoms and recent perceived psychological stress. Exploratory analyses suggest that the relations between ACC-anterior insula functional coupling and coping drinking motives may be confounded by anticonvulsant use.

Conclusion: Results suggest that a difference in ACC-anterior insula functional coupling during emotion processing may underlie alcohol use as a maladaptive coping mechanism in young adults with bipolar disorder.

Keywords: alcohol drinking; anterior cingulate cortex; anterior insula; bipolar disorder; drinking motives.

Figure 1.

Proposed causal model depicting hypothesized relations among neural processing of negative affective stimuli, coping drinking motives, and alcohol use in young adults with bipolar I disorder.

Figure 2.

Lateral and superior view of the a priori regions of interest (ROIs), including anterior cingulate cortex (ACC) and bilateral anterior insula and amygdala. ACC [MNI center coordinates: (x=0, y=22, z=35] and left and right anterior insula [MNI right center coordinates: (x=47, y=14, z=0); MNI left center coordinates: (x=−44, y=13, z=1)] were defined from a pre-defined network atlas in CONN and were originally derived from an independent component analysis (ICA) based on the Human Connectome Project (HCP) dataset of 497 subjects (Whitfield-Gabrieli and Nieto-Castanon, 2012). Bilateral amygdala ROIs were defined from the FSL Harvard-Oxford Atlas in CONN.

Figure 3.

Linear mixed models were used to examine relations between coping drinking motives and relative difference in anterior cingulate cortex (ACC)-anterior insula functional coupling during negative emotion processing. Greater coping drinking motives were significantly associated with greater increase in bilateral ACC-anterior insula functional coupling during negative emotion processing in those with bipolar disorder only. All analyses covaried biological sex and age of alcohol initiation. Bipolar Disorder type I: N=22; Typically Developing: N=26.