Low Regulatory Flexibility as a Mechanism of the Link Between Rumination and Internalizing Symptoms and Substance Misuse in College Freshmen

This study investigated low regulatory flexibility as a mechanism of the associations of rumination with affect, internalizing symptoms, and substance use and problems. 403 first-year college students completed an online baseline survey assessing rumination, regulatory flexibility, internalizing symptoms, alcohol use, cannabis use, alcohol problems, and cannabis problems. Roughly 2.67 months later, 261 of these participants completed a follow-up survey assessing internalizing symptoms and substance use and problems. Additionally, 71 of the 403 participants completed an experimental study. Thirty-three participants were randomly assigned to undergo a rumination induction, and 38 were assigned to a control condition. All lab participants underwent an interpersonal stress task during which regulatory flexibility was observed and completed pre-test and post-role-play measures of positive and negative affect. Experimental study results showed regulatory flexibility did not mediate effects of rumination induction on positive (indirect effect: standardized beta (β)=-0.01, unstandardized beta (b)=-0.12, 95% Confidence Interval (CI) [-0.64, 0.41], p=.66) or negative affect (indirect effect: β=0.01, b=0.17, 95% CI [-0.29, 0.63], p=.48). Longitudinal study results showed regulatory flexibility did not mediate associations between baseline rumination and follow-up internalizing symptoms (indirect effect: b=0.01, 95% CI [-0.03, 0.05], p=.57), alcohol use (indirect effect: b=-0.03, 95% CI [-0.09, 0.04], p=.39), cannabis use (indirect effect: b=0.10, 95% CI [-0.06, 0.26], p=.21), alcohol problems (indirect effect: b=-0.05, 95% CI [-0.18, 0.07], p=.40), or cannabis problems (indirect effect: b=-0.10, 95% CI [-0.36, 0.16], p=.43). However, rumination predicted greater internalizing symptoms (Incidence Rate Ratio (IRR)=1.26, b=0.23, 95% CI [0.08, 0.37], p=.003) and cannabis problems (IRR=1.73, b=0.55, 95% CI [0.23, 0.87], p=.001). Regulatory flexibility predicted fewer alcohol use days (IRR=0.76, b=-0.27, 95% CI [-0.49, -0.05], p=.015) and problems (IRR=0.58, b=-0.55, 95% CI [-0.95, -0.15], p=.007), and less cannabis use for women (IRR=0.59, b=-0.53, 95% CI [-0.92, -0.14], p=.007) and fewer cannabis problems for men (IRR=0.21, b=-1.55, 95% CI [-2.50, -0.60], p=.001). Lack of agreement about how best to measure regulatory flexibility makes it unclear whether null associations were due to measurement problems or actual null effects. Research on how best to measure this construct is a priority. Findings indicate rumination and regulatory flexibility may be promising intervention targets.