Prior research has found that new users of marijuana tend to be more impulsive in their behaviors under the influence of the drug, but had suggested that experienced marijuana users did not display the same impulsivity when under the influence. A recent research study, summarized in ScienceDaily for October 28, 2013, concluded that regular users of marijuana and cocaine respond to tasks with increased levels of impulsivity and lessened decision making skills.
Some background is necessary to understand this study. The significance of impulsivity in addiction relates to the tendency of impulsive impaired users to make poor decisions and possibly seek to use drugs. An impulsive individual would tend to make snap, poorly thought out, decisions. Impulsivity relates to the functioning of the limbic portion of the brain, which is the old or primitive brain in the back of the head. Addictive substances commonly disrupt the ability of the frontal cortex (new brain) to control impulsive, emotional reactions stemming from the limbic system of the old brain. In other words, an individual, unimpaired by drug use, confronted by peers (emotional response: “I want to fit in”) with the choice to use or not use a substance of abuse, would, hopefully, be able to use his/her critical thinking (frontal cortex) to override the emotional desire to fit in, and be able to decide that using the drug in the past has caused problems or is illegal and not worth the risk to use, or in some other way think through the issue of use or no use.
To elaborate, in the study under discussion, the subjects were healthy, regular users of cocaine and marijuana (61 of them), who, after use of these substances (controlled by a placebo (sugar pill)), were tested on their ability to reflect before making a decision, and on their ability to stop a behavior once started. The study also looked at the effects of drug use by these regular users of marijuana and cocaine on their executive functioning, that is, their ability to make reasoned decisions and to think critically, all functions of the frontal portion of the brain (prefrontal cortex).
The study concluded: “Both cannabis and cocaine increased impulsive responding, but in opposite ways. Under the influence of cannabis, subjects were slower, but made more errors. Cocaine administration caused the participants to react more quickly, but if participants had to control their impulses they made more errors. This increased impulsivity after drug use could increase the likelihood of developing addiction ***
***One hallmark of drug addiction is a disturbed relationship between the frontal cortex where decisions are made and the limbic system that organizes emotional responses and memory. These results indicate that cannabis could decrease the amount of control the frontal cortex exerts over behavior, while cocaine could increase impulsive responding from the limbic system.”
So, even an experienced user of marijuana or cocaine will, when under the influence of his/her drug, be more impulsive in behavior and will have difficulty accessing critical thinking skills to counteract emotional desires and impulses. This impulsivity and impaired judgment can have consequences beyond drug use, such as, impaired driving, impaired decisions in relationships, sexual decision making, to name a few.
As always, comments are invited. Jan Edward Williams, www.alcoholdrugsos.com, 10/29/2013.
