Adolescent Cannabis Use is Associated with Regional Decreases in Cortical Volume and Greater Decreases in Males than Females
Mona Darvishi of The Ohio State University reported that adolescent cannabis use is associated with regional decreases in cortical volume in 10 of 42 brain regions.
In two of these regions, the superior frontal gyrus and the caudal middle frontal gyrus, there was a significant drug-by-sex interaction with males having significantly greater volume reductions. They conclude “Our findings, combined with existing research on marijuana users, suggest that marijuana use is associated with brain structure, with potential sex-specific effects”
Young Men at Highest Schizophrenia Risk From Cannabis Abuse
Roughly 15% of schizophrenia cases among young males may be preventable by avoiding cannabis use disorder (CUD). Not only does cannabis abuse markedly increase the risk of schizophrenia, its use has transgenerational effects such that offspring from a cannabis user are more prone to use opiates.
Editors Note: Youngsters need to know two things.
1. Any supposedly legitimate drug bought on line may look like the real thing, but it is all-too-often laced with fentanyl which can kill someone in 5 minutes. No street-bought drug is safe, no matter how real it looks.
2. Marijuana will not kill you, but can make you psychotic for the rest of your life. The widely circulated notion that pot is safe is just a conspiracy by the plant growers to make money and by politicians who are ignorant of the facts. Pot doubles the rate of paranoia in the general population and if you have a good functioning genetic (val158val) version of COMT, this works too well to deplete dopamine in the prefrontal cortex and further increases the risk of paranoia and psychosis.
Cannabidiol Reduces the Anxiety Induced by Simulated Public Speaking in Treatment-Naïve Social Phobia Patients
M M Bergamaschi, et al reported in Neuropsychopharmacology volume 36, pages 1219–1226 (2011) that the one of the ingredient in cannabis, the diol or cannabidiol (CBD), containing none of the usual THC which make up the vast majority of plant-based marijuana, reduces the anxiety Induced by simulated public speaking in treatment-naïve social phobia patients. They used “CBD (600?mg) in powder, ?99.9% pure (kindly supplied by STI-Pharm, Brentwood, UK and THC-Pharm, Frankfurt, Germany),… dissolved in corn oil.” This CBD has shown efficacy in other anxiety disorders and is FDA approved for one form of seizure disorder. This pure form of CBD is very expensive and usual preparations of available cannabis contain mostly THC and only minute amounts of CBD. Thus, the generalizability of these results to people using the widely available preparations of cannabis is extremely unlikely.
Cannabidiol (CBD) does not make cannabis safer
Amir Englund et al reported in Neuropsychopharmacology in A randomised, double-blind, cross-over trial of cannabis with four different CBD:THC ratios that CBD did not protect against the adverse effect of THC. These included impaired delayed verbal recall ( p?=?0.001) and induced positive psychotic symptoms on the PANSS ( p?=?2.41?×?10–5).
Editors Note: Not only does marijuana impair memory, it is a risk factor the onset of bipolar disorder and schizophrenia. When pot is used by a person with a unipolar or bipolar mood disorder, there are increases in depression and anxiety and an overall less favorable course of illness. If a person with a mood disorder uses heavy amounts of marijuana, they could consider buying N-acetylcysteine (NAC) 500mg and increasing the dose to 1,000mg twice a day within a week as this has been shown to decrease drug use compared to placebo in adolescents and young adults using and abusing pot. Most people who sell pot, are not well-informed about its dangers and just want to make money.
Adolescent Delta-9-tetrahydrocannabinol induces long-term neuronal disturbances in dorsal vs. ventral hippocampus
De Felice et al reported in Neuropsychopharmacology (2022) how adolescent THC exposure in a rodent model can induce significant morphological disturbances and glutamatergic signaling abnormalities in the hippocampus. The dorsal hippocampus is critical for cognitive and contextual processing, whereas the ventral region is critical for affective and emotional processing. Adolescent THC exposure induces long-lasting memory deficits and anxiety like-behaviors concomitant with a wide range of differential molecular and neuronal abnormalities in dorsal vs. ventral hippocampal regions.
Editors Note: While these data are in rodents, they provide insights into how THC use in adolescents exerts memory deficits and anxiety-like behavior in adulthood by dysregulation of glutamate signaling in the hippocampus. These data converge with data in humans. The bottom line is: use of marijuana in adolescence is not good for brain function, cognition, and behavior in adulthood.
Cannabis Withdrawal Syndrome Occurs in Almost Half of Regular Users
A recent systematic review and meta-analysis by researcher Anees Bahji and colleagues in the open access medical journal JAMA Network Open describes the symptoms and prevalence of cannabis withdrawal syndrome.
The most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) indicates that cannabis withdrawal syndrome “requires the presence of at least 3 of the following symptoms developing within 7 days of reduced cannabis use: (1) irritability, anger, or aggression; (2) nervousness or anxiety; (3) sleep disturbance; (4) appetite or weight disturbance; (5) restlessness; (6) depressed mood; and (7) somatic symptoms, such as headaches, sweating, nausea, vomiting, or abdominal pain.”
According to Bahji and colleagues, cannabis withdrawal syndrome occurred in 47% of regular users. Higher rates of withdrawal were found among those in clinical settings, those who also used tobacco or other substances, and those who used cannabis daily.
Bahji and colleagues write that while many people believe that cannabis is relatively harmless, it actually has a variety of associated risks. Short-term risks include impaired short-term memory and motor coordination, altered judgment, paranoia, and psychosis. Long-term effects include addiction, altered brain development, poor educational outcomes, cognitive impairment, diminished quality of life, increased risk of chronic respiratory tract and psychotic disorders, injuries, motor vehicle collisions, and suicide.
The researchers warned that users of cannabis may resume cannabis use to allay the depression and anxiety symptoms that are part of the withdrawal syndrome, perpetuating the long-term withdrawal cycle.
Bahji and colleagues suggest that because of the high prevalence of the withdrawal syndrome, doctors should screen patients for cannabis withdrawal, particularly men and frequent cannabis users. They write, “Clinicians should be aware of CWS as it is associated with clinically significant symptoms, which can trigger resumption of cannabis use and serve as negative reinforcement for relapse during a quit attempt.” Doctors can offer support for those reducing their cannabis consumption.
Cannabis Use in Adolescence Linked to Depression and Suicidality in Young Adulthood
In a meta-analysis published in the journal JAMA Psychiatry in 2019, researcher Gabriella Gobbi and colleagues analyzed findings from 11 studies including a total of 23,317 participants and found that cannabis use in adolescence (before age 18) was associated with a significantly increased risk of depression, suicidality, and suicide attempts in young adulthood (between 18 and 32 years of age).
The researchers did not find a link between cannabis use and anxiety.
Editor’s Note: Cannabis use is not as harmless as many teens may believe.
In Animal Model, Long-Term THC Exposure Interferes with Cortical Control of the Nucleus Accumbens
In an article in the journal Biological Psychiatry, researchers Eun-Kyung Hwang and Carl R. Lupica reported that in rats, long-term use of THC (tetrahydrocannabinol) weakens input from the cortex to the reward area of the brain, the nucleus accumbens (NAc). Long-term THC use also strengthens connections to the NAc from emotional control (limbic) regions, such as the basolateral amygdala and ventral hippocampus. Hwang and Lupica reason that this shift from cortical control of the NAc to limbic control likely contributes to the cognitive and psychiatric symptoms associated with cannabis use.
Editor’s Note: Street marijuana largely contains THC rather than CBD, the beneficial, anxiety-reducing component of cannabis. Cannabis products are being decriminalized, but it is important to remember that those with THC are linked to cannabis use disorder and increased susceptibility to psychiatric illness. Patients with bipolar disorder who use marijuana also have a more adverse course of illness than those who do not use it.
One Hit of THC Tied to Psychotic Symptoms in Adults with No History of Mental Illness
In a meta-analysis published in the journal Lancet Psychiatry, researcher Guy Hindley and colleagues reported that in otherwise healthy adults, a single dose of THC (equivalent to smoking one joint) produced transient psychotic symptoms.
The meta-analysis included 9 studies with a total of 196 participants. The researchers included studies in which participants took tetrahydrocannabinol (THC, the psychoactive component in marijuana) or placebo, and psychotic symptoms were measured.
The researchers also sought out studies in which cannabidiol or CBD was given in combination with THC, but there were not enough of these to derive significant results. CBD does not produce schizophrenia-like symptoms on its own, and some think it may have anti-psychotic effects, but findings on this topic have been mixed.
Taking THC had a large effect size on total psychotic symptoms and negative symptom severity (such as emotional flatness or avolition). It also had an effect on positive symptom severity (for example, hallucinations or delusions). The effects were larger with intravenous administration than with inhaled administration, and tobacco smokers had less severe positive symptoms.
Of four studies that included CBD, only one found that CBD reduced THC-induced psychotic symptoms.
Editor’s Note: Longer-term use of marijuana in adolescents and young adults doubles the risk of psychosis, and other data suggest that chronic use of marijuana at high doses can be associated with new onset of a diagnosis of bipolar disorder or schizophrenia. As cannabis products are being decriminalized around the US, it is worth noting some of the risks of marijuana use, particularly marijuana with a high level of THC.
Cannabis May Produce More Brain Changes in Teens with Bipolar Disorder than in Healthy Teens
At the 2019 meeting of the International Society for Bipolar Disorders, researcher Benjamin Goldstein of Sunnybrook Research Institute in Toronto reported that adolescents with bipolar disorder who smoked marijuana had greater deficits in certain brain areas than did adolescents who did not have bipolar disorder. The areas affected included the dorsal lateral and rostral middle frontal cortex, and middle cortex. Goldstein concluded, “Adolescents with [bipolar disorder] may be particularly sensitive to the neurostructural effects of cannabis.”
Marijuana in general causes adverse changes in brain structure and cognition and vulnerability to paranoia and psychosis. Heavy use in adolescence is associated with an increased incidence of the onset of bipolar disorder and schizophrenia. The Goldstein data suggest several possible causal mechanisms. Those with bipolar disorder may already have brain abnormalities that are exacerbated by marijuana use. Alternatively, marijuana and bipolar disorder together may impact brain structure more than either factor alone would.
