Author: Gary Jackson

Does Marijuana Kill Brain Cells?

Most of these studies have revealed changes in brain function, often without notable performance deficits, suggesting that performance may be maintained through recruitment of brain regions not typically engaged in a particular cognitive function. In contrast, schizophrenic patients with cannabis abuse had better emotional memory than schizophrenic patients who did not use cannabis, possibly by reducing negative symptoms (91). These changes are most evident among adolescent users or those with early onset of cannabis use, as adolescence represents a critical period of neurodevelopment, making youth more vulnerable to exogenous influences, including cannabis. Accordingly, frequency and magnitude of use, product choice/potency, mode of use, and age of the consumer are all likely to influence the effects of cannabis on the brain.

If users decide to drive while high, they can endanger their lives and the lives of others. • Amount of tetrahydrocannabinol (THC) in marijuana (in other words, the concentration or strength),
• How often it is used,
• Age of first use, and
• Whether other substances (for example, tobacco and alcohol) are used at the same time. It is also worth noting that a subset of the study participants who used marijuana in adolescence had slightly better working memory scores than those who did not use marijuana.

What about that infamous IQ study?

Potential effects on the trajectory of brain morphology and cognition, therefore, should be considered. The goal of this review is to update and consolidate relevant findings in order to inform attitudes and public policy regarding the recreational and medical use of cannabis and cannabinoid compounds. Long-term and frequent marijuana use probably affects cognitive functions such as attention, memory, and learning, but more research needs to be done to understand how.

• Extreme care is warranted when evaluating the impact of cannabis on the still-developing adolescent brain.
• This suggests there is a range of recreational use that may not lead to long-term cognitive issues.
• Early, heavy use may then interfere with educational and vocational training, leading to long-term consequences in adulthood.
• For one, their cognitive effects are more pronounced among young people.

Memory has been the cognitive domain most consistently impaired, with verbal learning and memory tasks particularly sensitive to the acute (142–144) and chronic (134) effects of cannabis. Several individual aspects of memory appear to be affected (46,134,145,146), with the most robust effects on verbal learning, including decrements in measures of encoding, recall, and recognition (see (134) for review). Associations between poorer performance in regular cannabis users and frequency, quantity, duration, and age of onset of cannabis use have also been reported (97,98,114,147,148). In long-term users, lasting impairments in memory and attention worsened with increasing years of regular cannabis use (135,140,149,150).

What should you do if you experience cognitive effects of cannabis?

If you drink or eat pot, it may take many hours for you to fully sober up. You may not always know how potent your recreational marijuana might be. However, cumulative exposure didn’t appear to affect processing speed or executive function.

The short-term side effects of marijuana depend on factors like the type of marijuana you use and whether or not you’ve consumed other substances, like alcohol and other drugs. Some studies link marijuana to cognitive decline, particularly in adolescents. Other studies show positive correlations between marijuana use in older adults and cognitive functioning.

Cannabis (Marijuana) Research Report

The study also found that people who knew these long-term cannabis users well observed that they had developed memory and attention problems. The above findings persisted even when the study authors controlled for factors such as dependence on other drugs, childhood socioeconomic status, or baseline childhood intelligence. Recent research published in The American Journal of Psychiatry closely followed nearly 1,000 individuals in New Zealand from age 3 to age 45 to understand the impact of cannabis use on brain function. The research team discovered that individuals who used cannabis long-term (for several years or more) and heavily (at least weekly, though a majority in their study used more than four times a week) exhibited impairments across several domains of cognition. Contrary to these findings, recent studies have shown that THC can promote neurogenesis, restore memory and prevent neurodegenerative processes and cognitive decline in animal models of Alzheimer’s disease (151–153).

In test of inhibitory control, such as go/no-go or stop-signal tasks, THC administration increased reaction time in occasional and heavier cannabis users (116,118,122,124), but other findings in chronic users were mixed (125–129). At this time, scientists are not fully aware of the long-term effects of Marijuana use on the brain. They have, however, found a correlation between the use of Marijuana during brain development and decreased IQ later in life.

It May Affect Your Mental Health

Chronic THC exposure may hasten age-related loss of hippocampal neurons. In one study, rats exposed to THC every day for 8 months (approximately 30% of their lifespan) showed a level of nerve cell loss at 11 to 12 months of age that equaled that of unexposed animals twice their age. It’s short for cannabidiol, a substance found in both marijuana and hemp plants. CBD can be made into CBD oil and sold as pills, gels, creams, and other formulas. Some people use CBD to treat pain, seizures, and other health problems. But scientists aren’t yet sure how well it works or if it’s safe over the long term.

• Some studies suggest that THC has potentially permanent neurotoxic effects that impair people’s verbal learning, memory, and focus.
• Cannabis is the most widely used illicit substance worldwide, with an estimated 183 million past-year users in 2017 (4).
• The Iowa Gambling Task, delayed discounting tasks, and risk-taking decision-making tasks have been used.
• Cannabinoids, such as THC, and naturally occurring endocannabinoids may have significant effects on brain function and development.
• First, it was among the first large, longitudinal (long-term) studies to assess marijuana use and cognitive functioning.

More research needs to be done to fully understand the effects of marijuana on the brain of persistent cannabis users. Increasing usage rates by people in every age range in the United States (74,75) highlight the need to address unanswered questions about the effects of cannabis on the brain (see Table 1). Legalization has enhanced public awareness of questions about the effects of cannabis, and may also facilitate the recruitment of participants for observational studies to answer these questions. Rapidly advancing data collection supported by funding for large-scale longitudinal studies, such as the Adolescent Brain Cognitive Development Longitudinal Study, will be addressing many of these questions (Collaborative Research on Addiction at NIH). Because of the increased and widespread availability and use of cannabis, and FDA-approved medical uses of cannabinoid compounds, information regarding potential untoward effects and safety limits is needed to guide public policy. Of primary concern are potential effects on the brain and cognition, which are reviewed here.