- Details
- Hits: 1679
Journal of Neuroscience 6 March 2019, 39 (10) 1817-1827; DOI: https://doi.org/10.1523/JNEUROSCI.3375-17.2018
Abstract: Rates of cannabis use among adolescents are high, and are increasing concurrent with changes in the legal status of marijuana and societal attitudes regarding its use. Recreational cannabis use is understudied, especially in the adolescent period when neural maturation may make users particularly vulnerable to the effects of Δ-9-tetrahydrocannabinol (THC) on brain structure. In the current study, we used voxel-based morphometry to compare gray matter volume (GMV) in forty-six 14-year-old human adolescents (males and females) with just one or two instances of cannabis use and carefully matched THC-naive controls. We identified extensive regions in the bilateral medial temporal lobes as well as the bilateral posterior cingulate, lingual gyri, and cerebellum that showed greater GMV in the cannabis users. Analysis of longitudinal data confirmed that GMV differences were unlikely to precede cannabis use. GMV in the temporal regions was associated with contemporaneous performance on the Perceptual Reasoning Index and with future generalized anxiety symptoms in the cannabis users. The distribution of GMV effects mapped onto biomarkers of the endogenous cannabinoid system providing insight into possible mechanisms for these effects.
SIGNIFICANCE STATEMENT: Almost 35% of American 10th graders have reported using cannabis and existing research suggests that initiation of cannabis use in adolescence is associated with long-term neurocognitive effects. We understand very little about the earliest effects of cannabis use, however, because most research is conducted in adults with a heavy pattern of lifetime use. This study presents evidence suggesting structural brain and cognitive effects of just one or two instances of cannabis use in adolescence. Converging evidence suggests a role for the endocannabinoid system in these effects. This research is particularly timely as the legal status of cannabis is changing in many jurisdictions and the perceived risk by youth associated with smoking cannabis has declined in recent years
- Details
- Hits: 1586
Depression, anxiety, and trauma diagnoses and symptoms were associated with higher odds of cannabis use among pregnant women in California. These results support previous qualitative findings that pregnant women self-report using cannabis to manage mood and stress3,4 and suggest a dose-response association, with higher odds of cannabis use associated with co-occurring depressive and anxiety disorders and greater depression severity. However, research is needed to determine the direction of these associations, because cannabis use might also cause or worsen mental health problems during pregnancy.
- Details
- Hits: 1689
There were no significant impacts on physical or emotional functioning, and low-quality evidence of improved sleep and patient global impression of change. Evidence for effectiveness of cannabinoids in CNCP (Chronic Non-Cancer Pain) is limited. Effects suggest that number needed to treat to benefit is high, and number needed to treat to harm is low, with limited impact on other domains. It seems unlikely that cannabinoids are highly effective medicines for CNCP.
- Details
- Hits: 1826
9th Feb 2020
Psychosis link to high potency drug must be investigated, warn mental health chiefs
Rethink Mental Illness charity warns over damaging effects of cannabis on the mind. Photograph: David Bebber/REUTERS
One in 20 adults would take cannabis on a regular basis if it were legalised, similar to the number of people who currently use it, according to a poll for a leading mental health charity.
A particular concern is the use of high potency cannabis, or “skunk”, which increases the risk of developing psychosis. Psychosis can be a symptom of mental illness, including schizophrenia and bipolar disorder.
Sir Robin Murray, professor of psychiatric research and chair of the Rethink Mental Illness Clinical Advisory Group, said high potency cannabis was responsible for a third of all new patients in London being diagnosed with psychosis. “This is a clear indicator that our current system is not working,” Murray said.
Many pro-legalisation groups argue it would see the potency levels capped, reducing harmful effects, but Murray is dubious. “In the US, states that have legalised cannabis for recreational purposes have seen an increase in the use and potency of cannabis, and even more cannabis-related problems.