Two recently published scientific studies have shed new light on the often confusing and conflicting information that we have on both marijuana and cocaine consumption, and are proving to be most informative and useful in tackling cases of drug addiction.

In the first study, which involved only cannabis users, researchers found that dopamine levels in a part of the brain called the striatum were lower in people who smoked more cannabis and those who began taking the drug at a younger age. Dopamine, which is linked to motivation and action, can directly affect reactions such as lethargy, assertiveness and depression.

In a trial study using 19 regular cannabis users and 19 non-users of matching age and sex, the researchers used PET brain imaging to observe dopamine production in the striatum. The cannabis users in the study had their first experience with the drug between the ages of 12 and 18, and there was a direct correlation between the age the participant was when he began smoking and the levels of dopamine; the younger the age, the lower the dopamine levels. This trend was also visible in those who smoked more cannabis. Smokers who met diagnostic criteria for cannabis abuse or dependence had the lowest of all dopamine levels, thus giving more weight to the association between cannabis consumption and differing dopamine levels.

Researchers were surprised with the results, as it was not the outcome that they expected; the cannabis users in the study had all had psychotic experiences, including hallucinations, strange thoughts and bizarre feelings, and as such researches expected their dopamine levels to be higher (as dopamine production has been linked with psychosis). Instead, they found the opposite effect.

In the second test, 61 healthy regular cannabis and cocaine users took both drugs and a placebo in controlled conditions. The researchers then made them undergo a variety of challenges and tests, which required them to reflect before taking an action. “If a person’s tendency to be impulsive increases, they tend to make snap decisions and the error rate increases,” says lead researcher Janelle van Wel from Maastricht University.

Here the results were exactly as expected; both cannabis and cocaine increased impulsive responding, but in opposite ways. Under the influence of cannabis, subjects were slower but made more errors, and after cocaine administration the participants reacted more quickly but more erratically, thus making more mistakes. Ms. van Wel announced that: “This increased impulsivity after drug use could increase the likelihood of developing addiction.”

Taken together, the findings illustrated that cocaine and cannabis users had far more impulsive reactions under the use of drugs than when they had been given placebos.”These findings contrast with previous reports, which had claimed that these effects after cannabis administration only occurred in occasional users and not in heavy users,” says Ms. van Wel.

The results of these two important studies may help us gain further insight and understanding of the effect that marijuana and cannabis have on the human brain and body, and in so doing bring us a few steps closer to identifying the causes of addiction and the physical consequences that drug addiction has on the brain. Such knowledge of the process is vital in tackling addiction and reversing it.

Original reports:

http://www.sciencedaily.com/releases/2013/07/130701081053.htm

http://www.sciencedaily.com/releases/2013/10/131028100938.htm