Grant: Project Grant

Between 1 and 4% of Canadian adults develop Gambling Disorder (GD). Despite this relatively low rate of occurrence, the harm associated with GD (e.g., suicide, family breakdown, job loss, crime) has been found to equal that of clinical depression. There is currently no medication approved to treat GD. Relief of GD symptoms from medications tested to date is limited and dropout rates are high (average ~40%). Although psychological therapy seems to be more effective, dropout rates are also very high (39%). Mental inflexibility (MI; getting 'stuck' in a counterproductive pattern of thought) is a key challenge to treatment in GD. The Alzheimer's medication, memantine (MEM) has recently been found to improve MI in people with obsessive-compulsive disorder. An early study also found that MEM greatly improved GD symptoms and coincided with only 3% dropout over 10 weeks of treatment. This early study did not compare MEM to a placebo (inactive pill). Placebo effects (improvement due to the belief the pill will improve symptoms; 'self-fulfilling prophecy') are very large in GD medication studies, so it is not clear if the decrease in GD symptoms and low dropout rate in the early MEM study are due to the medication, a placebo effect or both. The proposed study will compare placebo to MEM in people with GD (30 per treatment group) to isolate the benefits of the medication. As a first step, this study aims to address practical aspects of comparing MEM to placebo, including a) ability to enroll 60 participants with GD over 3 years; b) whether dropout rate is lower for MEM than placebo, c) whether MEM side effects are manageable; and d) if participants are taking their doses as prescribed. The decrease in symptoms and MI for MEM vs. placebo will be assessed to identify trends. Results of this small study will show if a full-scale placebo-controlled clinical trial of MEM can be carried out in future, and if MEM is likely to reduce the symptoms of GD and the harm associated with it.