Young adults should heed the mounting evidence regarding marijuana’s effects on the young adult brain.
In a recent evidence-based review of research published in the Journal of Addiction Medicine, Dr. R.D. Crean et al bring forward the results of a wide array of evidence-based studies on the effects of marijuana use on cognition, identifying a number of areas of the brain’s “complex, executive function tasks” that are impaired by cannabis use.
The dimensions of brain functioning shown to have been hindered or harmed include:
- The ability to plan
- The ability to organize
- The capacity to control one’s emotions and behavior
Clearly, each of these harms is of concern for young adults who are trying to perform and compete in college and early career stages.
The review’s authors state up front “these deficits differ in severity depending on the quantity, recency, age of onset and duration of marijuana use.” However, what they also point out is those with marijuana-related impairment in their “executive” brain functions “have been found to have trouble learning and applying the skills required for successful recovery, putting them at increased risk for relapse to cannabis use.”
A number of statistics indicate the importance of recognizing the effects of cannabis on executive complex brain functioning and the timeliness of increasing treatment access for those struggling with marijuana-related dependence. These include:
- The increasingly widespread availability of marijuana and cannabis products—36 states currently allow marijuana to be prescribed for medical use and 18 states have made it legal for recreational use.
- There being research evidence 1 in 10 users of marijuana will develop a dependence upon it.
- Approximately 1 out of every 6 (roughly 300,000) admissions to substance abuse treatment in the U.S. is for cannabis-related disorders (second only to alcohol-related disorders).
The authors’ research review, however, also demonstrated there are acute and cumulative time-related effects on the brain’s higher functions associated with a person’s cannabis use. They found, for example, significant impairment in the following:
Regarding acute effects of cannabis on executive functions (0 to 6 hours after use) —
- Deficiencies in decision-making and planning related to response speed and accuracy
- Increased impulsive behavior
- Decreased inhibition of maladaptive responses
- Significant deterioration of working memory
- Increased amount of time to complete tasks
In terms of marijuana-use-related “long-term” effects (3 weeks or longer since last use) on complex brain functions, the authors’ research review determined the following areas of significance:
- Enduring and detectable deficits in decision-making, concept formation and planning
Unfortunately, many young adults see more widespread legalization as a kind of endorsement that marijuana must be safe. Clearly, marijuana use in young adults leads to both short and long term problems that they have not thought of previously.
As for the implications relating to treatment of cannabis dependence, a review was conducted of the studies of such and the authors found that psychotherapy has been shown to reduce cannabis use, but that no form of psychotherapy performs significantly better than another in terms of reduced use. Their recommendations include, “When a patient presents for treatment with a cannabis use problem, the treatment provider may wish to consider obtaining a neuropsychological assessment of executive functions, as deficits may have important implications for treatment outcome.”
Further, they offer another suggestion: “A first-line approach may be to expose these patients to cognitive rehabilitative strategies such as encouraging them to check and double-check their work, to give themselves ample time to complete a task, to build in delays before responding so they can weigh the costs and benefits of their actions instead of reflexively responding to situations and to write things down and use repetition and cues to remember important tasks and information.”
In regard to the clinical setting of a treatment center working to help those seeking recovery from cannabis dependence, the authors conclude the information brought forward by this research review can assist treatment providers (especially medical staff, therapists and counselors) in their ability to inform their cannabis-abusing patients more accurately and with greater credibility and confidence “of the cognitive liabilities associated with continued use,” and to help foster their ability to “better understand the impairments their cannabis-abusing patients experience in comprehending, processing and following-through on important health and treatment advice relevant to sustaining their recovery.”
 SAMSHA. Results from the 2007 National Survey on Drug Use and Health: National Findings. Rockville, MD: Office of Applied studies, DHHS; 2007.
 SAMSHA. Results from the 2006 National Survey on Drug Use and Health: National Findings. Rockville, MD: Office of Applied studies, DHHS; 2006
 Nordstrom BR, Levin FR. Treatment of cannabis use disorders: a review of the literature. Am J Addict. 2007;16(5):331–42