Human Drug Abuse
September 9, 2009
MDMA is a stimulant, often referred to as ecstasy. Ecstasy produces effects in the body such as increased tactile sensitivity, impaired memory and learning, and liver toxicity. The article I chose is entitled, “Memory impairment in abstinent MDMA users: a longitudinal investigation.”
The study discussed in the article stems from the idea that ecstasy decreases the activity of serotonin in the brain for an extended period of time after usage. Serotonin has been proven to be related to learning and memory. Because of this, it is hypothesized that those who use MDMA may be at risk for a great deal of long-term neurotoxin effects. The hippocampus may be particularly affected. Since the hippocampus is the area of the brain responsible for formulating new memories and learning, it is reasonable to hypothesize that MDMA users may have lasting impairments to their memory.
The study discussed in the article is performed over a period of one year. The purpose of the study is to validate or invalidate the idea that MDMA deteriorates memory and learning over time.
The study utilizes 15 MDMA users as participants. Participants were required to pass a drug test. Participants were eliminated due to factors such as dyslexia, pregnancy, eating disorders, and migraines. Most participants reported unusual sleeping patterns, which is common for MDMA users. Since sleep deprivation affects cognitive performance, participants were asked to sleep 7-9 hours for 7 nights. Participants also abstained from drug use for two weeks.
Participants completed the Wechsler Adult Intelligence Scale-III Vocabulary and Block Design subtests and the Rivermead Behavioral Memory Test. The study utilized the Rivermead Behavioural Memory Test to analyze “immediate and delayed recall.” Participants were then shown portraits and asked to remember the first and second names of the individuals pictured. Participants were then asked to recall those names immediately and after a short delay. Next, a belonging of the participant is commandeered during the study and placed somewhere within the room. The participant is told to ask for the object before leaving. An alarm is also set for 20 minutes in the future. The participant is asked to ask a specific question when the alarm goes off. Next, ten drawn objects are shown to the participant. The participant is asked to name those objects. After a delay, the participant is asked to select the previously viewed items from a group of 20.
The participant is presented with a story, verbally. The participant is asked to recall as much of the story as he/she can immediately and after a delay. The participant is also presented with five faces. A delay occurs and the participant is asked to choose the original five from a set of ten. Finally, the experimenter produces a route comprised of five parts in the room. Immediately, the participant is asked to re-draw the route.
The study found that continued usage of MDMA is in fact associated with a decrease in several aspects of memory. Retrospective memory appeared to be particularly affected. Some tasks did not decline with continued MDMA use. These included remembering to ask the experimenter a specific question after an alarm, remembering to deliver a message, and remembering to ask for the return of a belonging.
One year passed before subjects were tested again. After one year, test scores either decreased or remained static. Large declines in scores on the RBMT were found.
The study fully supported the idea that continued MDMA use is likely to negatively affect the ability to recall first and second names. It is also likely to affect the immediate ability to recall a route.
As with all correlational studies, more research is generally needed before drawing conclusions. It also must be noted that it is difficult to draw conclusions when working with polypro users. Prior studies have shown that drug users who had taken ecstasy amongst other drugs expressed impairments in memory. However, there has been no study comparing drug users who have not taken ecstasy to recreational drug users. Therefore, the possibility remains that the impairments in memory could be related to other drug use. Another concern was the self-report of drug consumption by participants. It is clearly heavily unreliable.