Marijuana and Health (1982) / Chapter Skim
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BEHAVIORAL AND PSYCHOSOCIAL EFFECTS OF MARIJUANA USE
BEHAVIORAL AND PSYCHOSOCIAL EFFECTS OF MARIJUANA USE
Pages 112-138
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From page 112... ...
Many psychological and neuropsychological studies have been conducted to investigate specific effects of marijuana on behavior. These include studies of intellectual functions, such as memory, attention, sequential information processing, and decision-making, as well as perceptual and psychomotor functions.
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From page 113... ...
A representative sample of studies will be reviewed here, and a summary table of 88 reports of the relationship between marijuana use and behavioral and psychosocial functioning is available from the Institute of Medicine by request. PERCEPTUAL AND PSYCHOMOTOR FUNCTIONS Acute Effects The studies reported here cover the range of commonly used doses*
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From page 114... ...
This finding on the long-lasting effects has very important implications, as will be discussed later when the effects of marijuana on driving are reviewed, and, therefore, such studies should be repeated by other investigators. While reaction time studies (as noted above)
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From page 115... ...
Sensory and Perceptual Functions Tests that measure a subject's ability to detect a brief flash of light show significant impairment by low to moderate doses (2-3 mg are examples) of smoked marijuana (Sharma and Moskowitz, l972, l973, l974; Moskowitz et al., l972, l974; Casswell and Marks, l973; Jones and Stone, l970)
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From page 116... ...
These investigators believe that the major deficit is in the attention-storage phase of learning. Oral Communication Marijuana use in low to moderate doses impairs oral communication, especially clarity of sequential dialogue with other persons (Dornbush et al., l97l; Paul and Carson, l973; Zeidenberg et al., l973; Crockett et al., l976; Miller et al., l977a-d, l978a,b, l979; Pfefferbaum et al., l977; Miller and Cornett, l978; Natale et al., l979; Belmore and Miller, l980)
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From page 117... ...
. Auto Accidents Simulator Studies A driving simulator is a laboratory instrument that requires the subject to perform a sample of the behavior required in automobile driving situations.
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However, there have been practical reasons why the roadside survey model of using breath samples obtained from accident drivers and comparing those to breath samples of randomly selected drivers who are passing the accident site in the same direction, the same time of day, and same day of the week has not worked for marijuana studies. Whereas there has been 97 percent cooperation for alcohol breath analysis, marijuana determination requires a blood sample, and only a minority of drivers willingly cooperate.
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From page 119... ...
Twelve percent of the fatally injured drivers and pedestrians in that study had been found to have A-9-THC in their blood. The presence of other drugs was also determined and a culpability index was developed.
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Chronic Effects Animal Studies Studies of chronic effects are necessary to determine whether a drug produces changes that persist after administration has stopped. In view of the theoretical possibility of cumulative or persistent marijuana effects, it is surprising that only a few laboratories have conducted experiments involving repeated dosing and testing for residual effects.
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From page 121... ...
Thus, the acute effects of marijuana are based on more solid evidence than are the reported chronic effects. Acute Effects The acute clinical effects of marijuana seem to occur on a continuum from mild dysphoria to acute brain syndrome.
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Such controlled observations of persons whose immediate prior mental status and whose dosage were known give a basis for concluding that acute adverse psychological reactions can occur under single moderate doses of marijuana. These effects are more likely at higher doses.
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. Acute Brain Syndrome Diagnostic criteria for the syndrome now called delirium and previously called acute brain syndrome appear in Diagnostic and Statistical Manual of Mental Disorders, Third Edition, l980 (DSM III)
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Chronic Effects Cannabis Psychosis Cannabis psychosis refers to a chronic psychotic condition (out of contact with reality) reportedly seen in heavy marijuana users, but extending beyond the period of acute intoxication.
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Many troubled individuals seek an "escape" into use of drugs; thus, frequent use of marijuana may become one more in a series of counterproductive behaviors for these unhappy people. The available evidence does not allow a sorting of the various possibilities in the relationship between use of marijuana and the complex of symptoms in the "amotivational syndrome." It appears likely that both self-selection and authentic drug effects contribute to the "motivational" problems seen in some chronic marijuana users (see Chapter 2)
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From page 126... ...
Thus, there is clinical evidence that use of marijuana by those who have previously used LSD increases the likelihood of recurrence of the LSD experience. Effects on Preexisting Mental Illness The only evidence available regarding this issue consists of case reports of patients who had recovered and apparently were doing well until they used marijuana.
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From page 127... ...
. Further evidence that mood changes are not attributable solely to the pharmacological action of marijuana comes from a study that found that elevation in mood occurred immediately before use of marijuana and immediately after, but that mood was not correlated with other indications of the subjective level of intoxication (Rossi et al., l978)
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From page 128... ...
Some animal studies demonstrate a learning deficit that persists for months after marijuana exposure has been discontinued, but human studies do not permit secure conclusions. The acute clinical effects of marijuana are fairly well established, although there is no general agreement as to how to classify them.
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From page 129... ...
None of the investigators has looked at effects on the very young daily marijuana user, who is regarded as potentially at high risk for damaging effects because of physiological and psychological immaturity. There is clinical evidence that marijuana use by former LSD users may precipitate a recurrence of LSD-type hallucinations known as a "flashback." Other clinical evidence raises the possibility that marijuana use can worsen preexisting mental illness.
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" The correlation of changes in a physiological marker, such as increased heart rate, with observations of behavioral effects should be encouraged.
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Psychopharmacology 52:239-24l, l977. Diagnostic and Statistical Manual of Mental Disorder, Third Edition (DSM III)
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Permanent learning impairment after chronic heavy exposure to cannabis or ethanol in the rat, pp.
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Johnston, L.D. The daily marijuana user.
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Kvalseth, T.O. Effects of marijuana on human reaction time and motor control.
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and Cornett, T.L. Marijuana: Dose effects on pulse rate, subjective estimates of intoxication, free recall and recognition memory.
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Effects of marihuana on reaction time and short-term memory in human volunteers. Pharmacol.
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Pharmacokinetics of drug effects on driving performance: driving simulator tests of marihuana alone and in combination with alcohol. Report to the National Institute on Drug Abuse, Contract No.
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From page 138... ...
Weil, A.T. Adverse reactions to marihuana, classification and suggested treatment.
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