Marijuana dependence appears to be very similar to other substance dependence disorders, although the long-term clinical outcomes may be less severe. On average, adults seeking treatment for marijuana abuse or dependence have used marijuana nearly every day for more than 10 years and have attempted to quit more than six times. It is important to note that marijuana dependence is most prevalent among patients suffering from other psychiatric disorders, particularly among adolescent and young adult populations (Gouzoulis-Mayfrank 2008). Also, marijuana abuse or dependence typically co-occurs with use of other drugs, such as cocaine and alcohol. Available studies indicate that effectively treating the mental health disorder with standard treatments involving medications and behavioral therapies may help reduce cannabis use, particularly among heavy users and those with more chronic mental disorders. Behavioral treatments, such as motivational enhancement therapy (MET), group or individual cognitive-behavioral therapy (CBT), and contingency management (CM), as well as family-based treatments, have shown promise.
Unfortunately, the success rates of treatment are rather modest. Even with the most effective treatment for adults, only about 50 percent of enrollees achieve an initial 2-week period of abstinence, and among those who do, approximately half will resume use within a year. Across studies, 1-year abstinence rates have ranged between 10 and 30 percent for the various behavioral approaches. As with other addictions, these data suggest that a chronic care model should be considered for marijuana addiction, with treatment intensity stepped up or down based on need, comorbid addictions or other mental disorders, and the availability of family and other supports.
Currently, no medications are available to treat marijuana abuse, but research is active in this area. Most of the studies to date have targeted the marijuana withdrawal syndrome. For example, a recent human laboratory study showed that a combination of a cannabinoid agonist medication with lofexidine (a medication approved in the United Kingdom for the treatment of opioid withdrawal) produced more robust improvements in sleep and decreased marijuana withdrawal, craving, and relapse in daily marijuana smokers relative to either medication alone. Recent discoveries about the inner workings of the endogenous cannabinoid system raise the future possibility of a medication able to block THC's intoxicating effects, which could help prevent relapse by reducing or eliminating marijuana's appeal.
The Science of Medical Marijuana
The potential medicinal properties of marijuana have been the subject of substantive research and heated debate. Scientists have confirmed that the cannabis plant contains active ingredients with therapeutic potential for relieving pain, controlling nausea, stimulating appetite, and decreasing ocular pressure. As a result, a 1990 Institute of Medicine report concluded that further clinical research on cannabinoid drugs and safe delivery systems was warranted.
At that time, dronabinol (Marinol®) and nabilone (Cesamet®) were the only FDA-approved, marijuana-based medications that doctors could prescribe for the treatment of nausea in patients undergoing cancer chemotherapy and to stimulate appetite in patients with wasting syndrome due to AIDS. These pills contained synthetic versions of THC, the main active ingredient in marijuana. Today, 25 years after their approval, the development of Sativex® marks the arrival of the second generation of cannabis-based medications. This new product (currently available in the United Kingdom and Canada) is a chemically pure mixture of plant-derived THC and Cannabidiol, formulated as a mouth spray and approved for the relief of cancer-associated pain and spasticity and neuropathic pain in multiple sclerosis.
Scientists continue to investigate the medicinal properties of THC and other cannabinoids to better evaluate and harness their ability to help patients suffering from a broad range of conditions, while avoiding the adverse effects of smoked marijuana. These efforts are bound to improve our understanding of the cannabinoid system and help us bring to market a new generation of safe and effective medications.