Marijuana Use and Co-occurring Mental Disorders
Author: Mark Gold, MD
Regular marijuana use has been associated with a range of acute and chronic mental health problems such as anxiety, depression, psychotic symptoms and neurocognitive impairments. However, the neural mechanisms for cognitive impairment, particular deficits in working memory and decision-making process, are not well understood.
What We Know About Marijuana
Primate studies have shown that sustained cannabis exposure results in sustained activation of Cannabinoid receptor-1 (CB-1) signaling and is correlated with the onset of neurocognitive deficits, as well as changes in brain structure and functional connectivity. Yet to date, only a handful of studies have endeavored to determine how, and to what extent, do CB-1 receptors mediate the effects of marijuana use on brain function in humans.
Mizrahi and Colleagues (2017) reviewed the best available evidence to provide an overview of cognitive deficits associated with regular and chronic use of marijuana. Moreover, there is concurrent evidence that regular use of marijuana alters neuronal function during challenges involving sustaining attention, multi-tasking, working memory, and time and space perception. For some, these deficits are mediated through the conscription of different brain regions and specific nuclei within these regions to perform compensatory functions for activities inhibited by marijuana intoxication.
This important finding further elucidates the function and role of the extensive EC system. Yet there are likely hundreds, if not thousands, of potential benefits within the vast universe of CB-1, CB-2 and, of course, CBD receptors. Paradoxically, there is the potential for considerable harm as new and novel illicit formulations are being developed by unscrupulous manufacturers and sellers of intoxicants who try and cash in by developing a new class of synthetic cannabinoids promising new, more intense and longer highs.
Why Does This Matter?
Simply stated, regular marijuana users may underachieve in school, career and nearly everything they endeavor to do. Why?
- Cannabis impairs memory, specifically the ability to retrieve and recall previously learned and stored information. This is how intelligence and competence is “tested” in academics and in the real world.
- Regular marijuana users can become emotionally absent and drone-like in their relationships. While they are high, they subjectively report that life is good and those they care about are relatively happy.
In other words, if they feel good (as a result of being high), they erroneously assume that they are behaving “good” and that those around them are content and happy. Research at the Scripps Institute shows quite the opposite. Interviews with spouses and children of regular users report that users are emotionally vacant, unavailable or narcissistic in their behavior. Their conversations are frequently obtuse, and sometimes bordering on bizarre.
“I used to wait for my dad to come home from work so he could throw the football or shoot hoops with me. But all he ever does is go into his “workshop” in the back of the garage, lock the door, turn on the fan and smoke his stuff. He comes out when dinner is ready and talks about really stupid stuff. It’s embarrassing. Then he just sits in his recliner and watches TV until he falls asleep. He never does anything.”
—-Jalen, age 13, Ann Arbor, Michigan
Cannabis users are impaired long after the “subjective” feeling of being high wears off. This is increasingly evident in the impaired driving data involving marijuana. The users claim, and science supports this claim, that they were no longer “high” when they were cited for DUI. But their impairment continued long after the high subsided. This is largely due to the lipophilic nature of cannabis versus alcohol, and most other drugs, which are hydrophilic. There is much to be learned.