Supplementary Material for: Motivational Interviewing for Cannabis Use Disorders: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> Cannabis is one of the most used drugs worldwide. There is no gold standard treatment for cannabis use disorder (CUD). Motivational interviewing (MI) has shown efficacy in some substance use disorders. Therefore, a systematic review was conducted to assess the effectiveness of MI in CUD. <b><i>Methods:</i></b> Randomized controlled trials or open-label studies published until September 2019 from 3 different databases (Pubmed, Scopus, and PsycINFO) were included, following the PRISMA guidelines and a predetermined set of criteria for article selection. Meta-analyses were conducted. The end point was determined as month 3, and 4 outcomes were analysed (abstinence rates, reduction in frequency of use, reduction in quantity of use, and reduction in cannabis use disorder symptoms) in 2 populations (adolescents and adults). <b><i>Results:</i></b> Forty studies were identified, of which 24 were performed in adults and 16 in adolescents. MI showed efficacy in achieving abstinence in both adults (odds ratio [OR] = 3.84, 95% confidence interval [CI] 2.40–6.16, <i>p</i> &lt; 0.0001) and adolescents (OR = 2.02, 95% CI 1.42–2.89, <i>p</i> &lt; 0.0001). MI showed efficacy in reducing frequency and quantity of use in adults but not in adolescents. Those adults who were in the MI group consumed less joints per day than those in the control group (mean difference = −0.69 joints per day, 95% CI −0.84 to −0.53, <i>p</i> &lt; 0.001), and they consumed on less days per month (mean difference = −3.9 days per month, 95% CI −7.47 to −0.34, <i>p</i> = 0.0317) than those in the control group. <b><i>Conclusions:</i></b> MI is an effective intervention to reduce cannabis use and achieve abstinence, especially among adults and patients with no prior history of psychotic disorder. Further investigation is needed to assess the effect on CUD symptoms. MI should be included in guidelines for treating cannabis use disorder as one of the essential psychological interventions.

<b><i>研究背景:</i></b> 大麻是全球范围内使用最广泛的精神活性物质之一，目前尚无针对大麻使用障碍（Cannabis Use Disorder, CUD）的金标准治疗方案。动机访谈（Motivational Interviewing, MI）在部分物质使用障碍的治疗中已展现出疗效。为此，本研究开展了一项系统综述，以评估动机访谈用于大麻使用障碍的临床效果。<b><i>研究方法:</i></b> 本研究检索了截至2019年9月收录于PubMed、Scopus及PsycINFO三个数据库的文献，严格遵循PRISMA指南及预先设定的文献筛选标准，纳入随机对照试验或开放标签研究，并开展Meta分析。本研究以随访第3个月为主要终点，在青少年与成人两个人群中分析4项结局指标：戒断率、使用频率降低幅度、使用量降低幅度及大麻使用障碍症状改善情况。<b><i>研究结果:</i></b> 本研究共检索到40项符合标准的研究，其中24项针对成人人群，16项针对青少年人群。结果显示，动机访谈可显著提升成人（比值比[Odds Ratio, OR] = 3.84，95%置信区间[Confidence Interval, CI] 2.40–6.16，P < 0.0001）与青少年（OR = 2.02，95% CI 1.42–2.89，P < 0.0001）的戒断率。动机访谈可有效降低成人的大麻使用频率与使用量，但对青少年人群无显著效果。相较于对照组，动机访谈组的成人每日吸食大麻烟支数量更少（均数差[Mean Difference, MD] = −0.69 支/日，95% CI −0.84至−0.53，P < 0.001），且每月吸食大麻的天数也更少（MD = −3.9 天/月，95% CI −7.47至−0.34，P = 0.0317）。<b><i>研究结论:</i></b> 动机访谈是一种可有效减少大麻使用并实现戒断的干预手段，尤其适用于成人及无精神病既往史的患者。未来仍需开展进一步研究以评估其对大麻使用障碍症状的改善效果。建议将动机访谈作为核心心理干预措施之一，纳入大麻使用障碍的临床诊疗指南。