HOW YOUR MIND CAN GO TO POT

Mowlam: A Joint Not Always Harmless

Mo Mowlam's admission that she smoked cannabis as a postgraduate in Iowa
has led to a shoal of confessions from other politicians who were students
in the 1960s and 1970s.

Dr Mowlam presumably accepted her joint well aware of its pharmacological
effects. Not so the guests of Gertrude Stein, who, when living in Paris in
the 1920s, was accustomed to bake cakes with various illicit substances.
Apparently, her tea parties, which included such names as Picasso,
Hemingway and Matisse, became so jovial that even artistic and literary
rivals were able to enjoy each other's company.

Dr Mowlam has said that her concern is with drugs that kill. Few would
argue with this principle, but she does not address the important issue:
the effect of cannabis on mental disease.

There is no record of any of Gertrude Stein's tea party guests suffering
from psychotic breakdowns after nibbling her ginger cake; one of my
patients was not so lucky. The patient was a most attractive and vivacious
woman in her sixties whose main interests were the Church, the Conservative
Party and her dog. Feeling that her birthday party was unlikely to be the
rave of the year, her student family included cannabis in the recipe for
the birthday cake. The patient suffered an acute psychotic breakdown with
the most disturbing hallucinations. After a short spell on anti-psychotics
she made an uninterrupted recovery.

Few, if any doctors, will deny that the symptoms of schizophrenia are made
worse by cannabis. This applies to both the positive symptoms - bizarre
behaviour following a breakdown in the normal thought pattern, with its
attendant delusions and hallucinations - and the negative symptoms, the
depression, lethargy and social withdrawal.

Whether taking cannabis actually causes schizophrenia is more contentious.
Possibly cannabis sometimes converts the schizo-typal to schizophrenic. If
my grandmother, uncle, or even a second cousin, let alone a parent, had
evidence of schizophrenic disease, cannabis smoking is one indulgence I
would eschew.

The likely sequence of events is that the propensity to develop
schizophrenia is inherited. Not every potential case will develop the full
blown psychiatric disease; this may well depend on the patient's
environment and lifestyle, their own medical history (even their delivery),
and the use, or otherwise, of such drugs as cannabis, LSD and even crack
cocaine.

A study of army recruits in Sweden - and no country is more liberal - found
that those who had used cannabis on more than 50 occasions had a sixfold
increase in the likelihood of developing schizophrenia compared with those
who had not tried it. Not all cases, like the cake-eating mother, developed
their psychotic symptoms soon after the event. The Swedish trial showed
that more often there was a gap of at least a year.

Driving skills: The Government announced this week that it is to
investigate the effects of cannabis on driving. Thirty years ago one of the
then great advocates of cannabis smoking gave me a lift to a debate on the
subject. Although he had been smoking cannabis, the drive itself was slow
but uneventful. When we arrived he parked at least 2ft from the pavement.
Earlier work has shown that, when driving, cannabis users overestimate the
likely effect of the drug. In consequence they try harder, drive more
slowly, even though their performance may seem little altered. These
experiments did not investigate the driver's reaction.

An interesting feature of cannabis is that its effect is related to IQ -
cannabis has less of an adverse influence on those with a high IQ than it
does on the older user, and those who are not quite so bright. The memory
and intellectual agility of some heavy habitual users is sometimes enhanced
after their first joint.