Motivational Interviewing (MI) has been used as an approach to enhance readiness for change and behavior modification in a range of addiction and substance use disorders. Large meta-analyses comparing MI with non-MI interventions point to mixed conclusions about the short-term and long-term effectiveness of MI, with participant, outcome, and delivery factors being important moderators. The current study aimed to assess the immediate (1–2 weeks) and long-term (18 months) effectiveness of MI when delivered at the first point of client contact at a community gambling help counselling service and to investigate whether practitioners’ MI adherent and non-adherent behaviors were significant predictors of change in client outcomes. There were 146 individuals presenting for gambling help counselling at an Australian not-for-profit organization who participated in this research. From the overall sample, 55% completed the 18 months follow-up assessment. Multilevel modelling showed a significant reduction in participants’ problem gambling severity and psychological distress, which was a small effect size change in the short-term and large effect size change by the 18 months follow-up. While MI adherent practitioner behaviors were not found to be significant predictors of improvement in participants’ problem gambling severity and psychological distress, MI non-adherent practitioner behaviors were significant predictors of deterioration in participants’ problem gambling severity and psychological distress. This study highlights the importance of excluding MI non-adherent (confront and persuade) practitioner behaviors in order to prevent deterioration in client outcomes.

动机访谈 (MI) 已被用作一种方法，以增强对一系列成瘾和物质使用障碍的改变和行为改变的准备。比较 MI 与非 MI 干预措施的大型荟萃分析表明，关于 MI 的短期和长期有效性的结论不一，参与者、结果和交付因素是重要的调节因素。目前的研究旨在评估在社区赌博帮助咨询服务中与客户首次接触时 MI 的即时（1-2 周）和长期（18 个月）有效性，并调查从业者的 MI 依从性和不依从行为是客户结果变化的重要预测因素。参与这项研究的澳大利亚非营利组织有 146 人参加赌博帮助咨询。从整体样本中，55% 完成了 18 个月的随访评估。多层次模型显示参与者的问题赌博严重程度和心理困扰显着降低，这是短期的小效应量变化和 18 个月随访的大效应量变化。虽然未发现 MI 坚持从业者行为是改善参与者问题赌博严重程度和心理困扰的重要预测因素，但 MI 非坚持从业者行为是参与者问题赌博严重程度和心理困扰恶化的重要预测因素。