Marijuana on the MIND: Assessing the Impact of Medical Marijuana

Over the last several decades, although marijuana (MJ) users have historically sought out MJ for recreational purposes, a growing number are exploring MJ for medical indications. Over one million medical MJ (MMJ) consumers are registered in the US, and this number continues to grow as the public becomes increasingly aware of and open to the potential therapeutic effects of MJ. Despite research focused on the neurocognitive effects of recreational MJ, few studies have investigated the specific effects of MMJ on cognition or other related clinical domains. The goal of this study was to determine whether MMJ patients would experience improvement in executive function, perhaps related to primary symptom alleviation. Changes in clinical state, quality of life, and related variables were also assessed to determine the overall impact of MMJ treatment. Preliminary data are presented from an ongoing observational, longitudinal study, which assesses the impact of MMJ treatment. To date, 33 patients certified for MMJ use completed baseline assessments and 17 of these so far have returned for their first follow-up visit three months after initiating treatment. Results suggest that overall, MMJ patients experienced improvement on several measures of executive functioning (i.e. problem-solving, planning, and inhibition). In addition, improvements in task performance were accompanied by alterations in brain activation patterns measured using neuroimaging techniques during the Multi-Source Interference Test (MSIT), a robust measure of executive function. On self-report questionnaires, patients also indicated improvements in clinical state, including significantly reduced sleep disturbance, decreased symptoms of depression, attenuated impulsivity, and positive changes in some aspects of quality of life. Further, patients reported a notable decrease in their use of conventional pharmaceutical agents from baseline, with use of opiates declining 42.8% and use of antidepressants decreasing 15%. While intriguing, these findings are preliminary and warrant further investigation, which is currently underway, and will include larger numbers of participants assessed over longer periods of time. Given the likelihood of increased MMJ use across the country, it is imperative to determine the potential impact of short- and long-term treatment on cognitive, clinical and quality of life related measures as well as the efficacy of MMJ treatment itself.