Marijuana psychomotor performance

Liguori, A., Gatto, C.P., and Robinson, J.H., Effects of marijuana on equilibrium, psychomotor performance, and simulated driving, Behav. Pharmacol., 9, 599, 1998. 

The most common behavioral effect is a generalized decrease in psychomotor activity and decrements in some domains of psychomotor performance. These effects appear to be dose related, with more pronounced changes associated with greater amounts of marijuana taken in. The general decrease in motor activity appears to be pervasive, and the state is described as associated w ith feelings of relaxation and tranquility. The only exception to this effect appears to be speech because marijuana use is associated with rapid or slurred speech, circumstantial talk, and loquaciousness. These speech effects often are observed more in the early smoking phase, followed by the more traditional relaxation. 

Two of the most characteristic signs of marijuana use are increased pulse rate and reddening of the conjunctiva. Decreases in blood pressure and in psychomotor performance occur. Pupil size is not changed by marijuana. The answer is (B). 

Acute physical and psychological effects. Marijuana intoxication has an adverse effect on attention span, short-term memory, and psychomotor performance. Anxiety and panic attacks can occur, primarily in new users who are not familiar with marijuanas eflFects. At very high doses, some people experience delusions and hallucinations. There are no cases of fatal marijuana poisoning and humans are very unfikely to be able to ingest a fatal dose. The eflFect of marijuana intoxication impairs motor and cognitive abilities necessary to safely drive a car or operate machinery. The extent to which marijuana is involved in auto accidents is unclear. Many motorists intoxicated with marijuana drive more slowly and carefully and take fewer risks. However, there is an increased risk of accidents after using marijuana, but marijuana alone does not appear to contribute a great deal to accidents. Marijuana in combination with alcohol does. 

Conventional research on the nature of marijuana intoxication tells us that the primary effects are a slight increase in heart rate, reddening of the eyes, some difficulty with memory, and small decrements in performance on complex psychomotor tests. 

The effect of marijuana on production can be two-fold. First, an individual who is working close to or at his maximum capacity would probably suffer a decrement in performance after smoking marijuana, which could not be compensated for by additional financial incentive for increased productivity. Second, if incentive was offered, which is many times the case in an industrial situation, the individual s interest in the incentive probably would be lessened. The effects of marijuana on psychomotor function would probably be more severe in individuals performing white-collar jobs where concentration and decision making are normal job requirements. 

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