Abstract

Background: Substance use motives refer to an individual’s reasons for engaging in substance use. Although the respective alcohol and cannabis literatures have linked specific substance-use motives to indices of use, less is known about motives in concurrent users, particularly examination of cross-motives (e.g., cannabis motives predicting alcohol use). Methods: The present work examined motives for use in a sample of concurrent users to assess relations between motives and alcohol and cannabis outcomes (quantity, frequency, and use disorder symptoms) using both variable- and person-centered approaches. Finally, the present work aimed to discern the impact of timeframe selection for defining concurrent use (i.e., past year, past two weeks). Participants (N = 524) consisted of individuals that endorsed having used both alcohol and cannabis in the past year with subsample (N = 192) of individuals endorsing past two-week concurrent use. Results: Univariate linear regression analyses revealed small to medium positive relations between all alcohol motives and alcohol outcomes and small to medium positive relations between cannabis social, coping, enhancement, and expansion motives and cannabis use. Regressions examining cross-motives and multivariate models revealed wide variability in relations. Mixture analyses revealed a three-class solution (i.e., High Motives, Positive Alcohol, and Low Conformity) for past year concurrent users and a two-class solution (i.e., Low Motives and High Motives) for past two-week concurrent users. Discussion: Examination of motive classes revealed differences in substance, particularly cannabis, outcomes as a function of class membership. Findings are useful in classifying concurrent users’ motives and highlight the importance of timeframe selection.

摘要

背景：物质使用动机是指个人从事物质使用的原因。尽管各自的酒精和大麻文献已将特定的物质使用动机与使用指数联系起来，但对同时使用者的动机知之甚少，特别是对交叉动机的检查（例如，预测酒精使用的大麻动机）。方法：目前的工作使用变量和以人为中心的方法检查了同时用户样本中使用的动机，以评估动机与酒精和大麻结果（数量、频率和使用障碍症状）之间的关系。最后，目前的工作旨在辨别时间范围选择对定义并发使用（即过去一年、过去两周）的影响。参与者（N= 524) 由支持过去一年同时使用酒精和大麻的个人组成，子样本 ( N = 192) 的个人支持过去两周同时使用。结果：单变量线性回归分析揭示了所有酒精动机与酒精结果之间的中小正相关关系，以及大麻社会、应对、增强和扩张动机与大麻使用之间的中小正相关关系。检查交叉动机和多变量模型的回归揭示了关系的广泛可变性。混合分析揭示了过去一年并发用户的三类解决方案（即高动机、积极酒精和低一致性）和过去两周并发用户的两类解决方案（即低动机和高动机）。讨论：对动机类别的检查揭示了实质上的差异，特别是大麻，结果作为类别成员的函数。调查结果有助于对并发用户的动机进行分类，并强调时间范围选择的重要性。