Amotivational Syndrome

Clinical observations of marijuana use in the 1960s led to the development of a label for a constellation of symptoms called "amotivational syndrome," which was thought to be a long-term effect of heavy marijuana use. Symptoms include apathy, decreased productivity, decreased energy levels, depression, inability to concentrate, loss of motivation, and decreased goal-directed behavior. Amotivational syndrome does not refer to the acute intoxication of marijuana but rather the general characteristics of heavy marijuana users even when they are not high from the drug. Many studies in the 1960s and 1970s sought to empirically validate the existence of the syndrome, yet all of the studies had methodological flaws that made it difficult to draw definitive conclusions. As the literature on marijuana use accumulated, research was conducted in controlled laboratory settings, yet only one study involving rhesus monkeys was able to demonstrate the existence of amotivational syndrome. Although the syndrome has not been empirically validated in research on humans, marijuana use has been shown to affect memory and attention, both of which are capacities that could be directly related to motivation levels in an individual.

In the late 1960s, David Smith named the cluster of symptoms associated with motivation levels in marijuana users "amotivational syndrome" as he had observed in adolescents a decreased desire to work or compete. Smith provided two case studies in which the symptoms stopped after a period of abstinence from marijuana. However, in 1982, Smith stated that the impairment in functioning that constituted the syndrome occurred only in a small percentage of users.

Harold Kolansky and William Moore conducted several studies in the early 1970s that provided evidence supporting the existence of an amotivational syndrome among heavy marijuana users. Participants had smoked marijuana 3 to 10 times per week for periods ranging from 16 months to 6 years. The authors reported that all participants demonstrated [Page 68]adverse psychological symptoms such as apathy, flattened affect, confusion, difficulty with short-term memory, and "sluggishness" in mental and physical responses to stimuli. These symptoms emerged when marijuana use was initiated and ceased when drug use stopped. The researchers also asserted that the observed symptoms were associated with longer durations and higher frequencies of marijuana use. The hypothesis that marijuana use led to a cluster of symptoms known as amotivational syndrome was supported by the correlation of severity of symptoms and the length of marijuana use, in addition to the fact that participants' symptoms lessened or stopped after marijuana use ceased. Kolansky and Moore also observed the presence of the syndrome in a sample of 38 adolescents in which they argued that the negative effects of marijuana use were particularly accentuated due to the developmental stage of the participants.

A study examining chronic marijuana exposure in the rhesus monkey provided further evidence for the existence of amotivational syndrome. Monkeys were exposed to marijuana daily for 1 year and pressed a lever for food pellets on a progressive ratio schedule (i.e., every time a pellet was received, more presses of the lever were required to receive another pellet). The researchers found that when exposed to marijuana, breaking points were significantly lower than they were for controls, but they returned to normal when exposure to marijuana was discontinued. Thus, the researchers posited that the result was equivalent to the amotivational syndrome hypothesized to exist in humans.

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