Attentional impulsivity in methamphetamine use disorder: Assessing its mediating role between nicotine dependence and methamphetamine use disorder severity in the Chinese population

Background Methamphetamine use disorder (MUD) lacks effective treatments. MUD, nicotine dependence, alcohol dependence, and trait impulsivity may be correlated, however, the precise magnitude of the correlation remains unclear between these four aspects. This study aimed to construct comprehensive models to analyze the mediating role of trait impulsivity on nicotine/alcohol dependence and MUD severity. Methods This study included 1230 participants from five drug rehabilitation centers in China. After semi-structured interviews and standardized tests, 163 participants were divided into three groups based on MUD severity. Trait impulsivity was evaluated using the Chinese version of Barratt Impulsiveness Scale, 11th version. Results The mediation analyses revealed that the positive direct effect of nicotine dependence on MUD severity was 0.319 (95% CI: 0.231, 0.413), and the positive indirect effect of nicotine dependence on MUD severity via trait impulsivity was 0.079 (95% CI: 0.040, 0.126), accounting for 19.85% of the total effect. However, the parallel multiple mediation analysis indicated that the indirect effects of nicotine dependence on MUD severity via motor impulsivity and non-planning impulsivity were invalid ( P  > 0.05). The positive indirect effect of nicotine dependence on MUD severity via attentional impulsivity (AI) alone was 0.064 (95% CI: 0.027, 0.109), accounting for 16.08% of the total effect. Conclusions Trait impulsivity, especially AI, mediated the positive effects of nicotine dependence on MUD severity in a Chinese population. In the context of the causalities, high levels of nicotine dependence and trait impulsivity can accelerate the progression of severe MUD. Smoking cessation and impulsivity reduction may help prevent MUD.