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From: Jim Rosenfield 
Newsgroups: talk.politics.drugs
Date: 14 Oct 94 20:39 PDT
Subject: Alcohol + MJ Toxicology
Message-ID: <1484000762@cdp>

From: Jim Rosenfield 

Found this on the DRUGABUS list, am reposting here for your use:

Hmmm, time to come out of lurker mode.  Here's the executive summary from a
1986 study -

The Interaction Between Alcohol and Marijuana
A Dose Dependent Study of the Effects on Human Moods and Performance Skills

Gregory B. Chesher
Helen Dauncey
John Crawford
Kim Horn

Psychopharmacology Research Unit
Department of Pharmacology
University of Sydney, NSW.

for the Federal Office of Road Safety (Australia)

Executive Summary

1. A study was designed to examine the effects of marijuana and alcohol when
taken alone and in combination on human skills performance and mood.

2. Four dosage conditions were employed for each drug (placebo and three
active doses). All possible combinations of these dosage conditions were
tested (ie 16 dosage groups).

3. Twenty subjects were used for each dosage group, the experiment employing
320 subjects in all. Each subject attended the laboratory on one occasion

4. Data collected were for psychomotor performance using a battery of
computer-presented tests, mood effects, subjective assessments of the nature
and degree of intoxication, and the subjective assessment of the effects of
the drugs on driving skills and willingness to drive a motor vehicle.

5. The performance battery included tests of human skills related to those
considered necessary to drive a motor vehicle with safety.

6. The population sample were recruited by advertisements on two Sydney
"Rock music" FM radio stations. All volunteers were non-naive as regards
marijuana use and were indeed heavy to very heavy users of this drug. The
extent of alcohol use by the volunteers was considered to be within the
normal range of use of this drug within the community.

7. The attitudes expressed concerning the dangers associated with the use of
the two drugs indicated that the population sample was heavily biased
against alcohol and in favor of marijuana

8. The subjective assessment of the doses of each drug employed indicated
that they were comparable. The subjects assessed the degree of intoxication
by marijuana as being of a similar intensity as that produced by alcohol.
The doses selected therefore appear to be relevant to those used within the
social experience of the volunteer population

9. Both drugs produced significant dose-dependent effects on the performance
measures, on the intoxication rating scales and on some of the mood

10. However, there were both quantitative and qualitative differences
between these effects, both on the performance measures and on the
subjective mood effects of the two drugs.

11. By far the major effects on these tests were those produced by alcohol.

12. The effect on skills performance of alcohol and marijuana when taken in
combination was essentially one of addition. Marijuana tended to increase
the intensity of the performance impairment produced by alcohol. However
there was evidence to suggest that the lowest dose of marijuana produced a
degree of antagonism of the effects of alcohol.

13. Marijuana had no effect on the absorption or metabolism of alcohol. The
blood alcohol concentration was not affected by any of the doses of
marijuana used.

14. The results of this study indicate clearly that alcohol and marijuana
are distinctly different drugs. The effects produced on the performance
measures were qualitatively and quantitatively different. In addition, the
differences in the nature of the drug-induced subjective intoxication and
the self-reported changes in mood effects such as anxiety and alertness,
strongly suggested different drug actions.

15. The ability to discriminate and assess the degree of intoxication with
alcohol was not affected by marijuana. However, the ability to assess the
intoxication due to marijuana was greatly affected by alcohol. The
subjective intoxication produced by marijuana appears to be of a more subtle
nature than that produced by alcohol.

16. Evidence is presented which suggests that under the influence of
alcohol, subjects engage in a "speed-accuracy trade-off". They are prepared
to make a hasty response to a question rather than to spend more time to
ensure a correct answer. This effect could be related to a risk-taking
behaviour. The results with marijuana on the other hand suggested a slower
and more careful approach to the problem, though as with alcohol, an
increased error rate in responses was recorded.

17. Evidence is presented which suggests that marijuana produces periodic
attentional lapses.

18. The results strongly suggest that the performance deficits and mood
changes produced by alcohol are of a greater magnitude than those produced
by marijuana.

19. Recommendations for directions of further research are made


whhheeeeewwww, apologies for the long post, but at least there won't be 30
replies asking for methodology, numbers, etc etc. (email privately for
specifics!!!).  Anyway, basically mj impairs driving,  but not as much as
alcohol. As for the NTSA study, I do wonder about the methodology.  Exposure
is obviously going to be a major factor and there is little doubt that there
are more people using alcohol than mj, so of course there will be more
alcohol related accidents (or did they control for this? - I haven't read
it). I also suspect that people who have been drinking may be more likely to
drive afterwards than people using mj.  In any case legalisation of more
drugs (which I am *for* incidentally) will require cheap accurate techniques
for measurement of levels of intoxication to allow enforcement of any
restrictions (eg don't smoke and drive).  IMHO, this perhaps is one of the
few legitimate anti-legalisation arguments.


David Steadson, Senior Research Assistant
Social and Preventive Medicine, University of Queensland
Brisbane, Australia.