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.