Tag Archives: marijuana

Marijuana Dependency “Wrongly Skewed Toward Men”: Review

A new review claims that research conducted on marijuana dependency has been skewed incorrectly towards men. Questions included in the criteria for diagnosing the condition such as, “Have you ever operated machinery or driven a truck while intoxicated from marijuana use?” are examples of a bias toward identifying and treating males with this issue.

Gender Bias Evident in Results

Researchers estimate that 12 percent of male and 5.5 female marijuana users are dependent on the drug. Gender bias has resulted in women being markedly underrepresented in these figures.

There has also been little work done on marijuana psychosis in parts of the world where marijuana use is significant. Most research is focused on gathering information in Europe, America and Australia. The impact of marijuana use in Asia, Africa and the Middle East is not being noted, and not much is known about statistics on marijuana psychosis in these parts of the world.

Ian Hamilton, from the University of York’s Department of Health Sciences, stated that about 10 percent of marijuana users are at risk of developing a dependence on the drug. He pointed out that diagnostic criteria must be updated to ensure the problem is represented accurately.

Mr. Hamilton confirmed that, “male-oriented questions” set the criteria for marijuana abuse lower for men than for women and that this fact could account for the difference in male and female dependence statistics. He also said that researchers have a limited understanding of the effect that marijuana dependence has on women and the effectiveness of treatment options for them.

More Details About Marijuana Dependence Needed

The review asserts that acquiring more details regarding marijuana dependence figures will help public health agencies when identifying and reaching out to high-risk groups.

Mr. Hamilton also said that most people who use marijuana won’t become dependent on it. Those who do become harmed by the drug won’t be “drawn equally from the population.” Instead, these people will be made up of some of the most vulnerable and disadvantaged members of society. He stated this will be the same situation “…as with problems associated with other drugs” and that problematic marijuana use, like other drug use, is only one of the advantages affecting these groups.

Heavy Marijuana Use May Decrease Dopamine in the Brain

molecular psychiatry evidence of marijuana dependenceThe results of a recent study have found that heavy marijuana use may decrease the level of dopamine released in the brain. Dopamine is a chemical transmitter that sends signals to the brain and is involved in movement, as well as learning, memory, cognition and pleasure.

Dr. Anissa Abi-Dargham, a professor of psychiatry at Columbia University Medical Center and a lead author of the research paper, said that it was important to look at the “addictive effects of cannabis on key portions of the brain.” The researchers found evidence of lower dopamine release in the striatum, which is the portion of the brain involved in attention, working memory and impulsive behavior.

The results of previous research studies have found a link between addiction to “harder drugs,” like heroin and cocaine, result in similar effects on dopamine release in the brain. Evidence of similar effects on dopamine release had not been found up to this point.

Study participants were 11 adults aged 21-40 who were described as being “severely dependent” on marijuana and 12 healthy control subjects who did not use cannabis. The group who were marijuana users started using the drug at an average age of 16, were dependent on it at about age 20, and were dependent on it for seven years. In the 30 days before the start of the study, almost all users in this group had smoked marijuana every day.

Positron emission tomography (PET) was used to track a radio-labelled molecule which binds to dopamine receptors in the brain. Researchers noted the level of dopamine released in the striatum, its subregions, and other regions outside of the striatum (thalamus, midbrain and globes pallidus).

To ensure that the marijuana group did not continue using the drug during the study, they stayed in the hospital for a week to ensure that they practiced abstinence. The participants were scanned before and after taking an oral amphetamine, which would cause the brain to release dopamine. The percent change in the binding of the radio tracer was used to indicate the participants’ capacity for dopamine release in their brain.

When compared with the control group, the cannabis users had much lower dopamine release in their striatum. Researchers also looked at the connection between dopamine release in a specific area of the striatum and cognitive performance on working memory and learning tasks. Lower dopamine release resulted in worse performance in both types of tasks, and this result was seen in all members of the marijuana group.

Dr. Abi-Dargham said that researchers were unable to determine whether the decreased dopamine was present before they started using marijuana or the result of their heavy drug use. She did say that long-term heavy marijuana use may impair a person’s dopaminergic system, resulting in a number of negative effects on both learning and behavior.