WHAT IS THE LONG-TERM EFFECT OF CANNABIS?

It helped her relax for a decade, but five years after kicking the
habit she suffers sleepless nights and anxiety. Is the weed coming
back to haunt her? Three experts have their say

For about 10 years I smoked cannabis regularly if not excessively. In
the evenings I'd get home from work and have a joint to unwind, and I
smoked about the same amount at weekends. I used it to help me relax
and sleep better. About five years ago I stopped doing it - I just got
out of the habit. Now I keep reading about the effect that strong
grass like skunk can have on mental health and all the reports have
got me worried about the long-term health implications of dope. I'm a
39-year-old woman and recently have had quite unpleasant bouts of
anxiety and insomnia - might this be caused by my smoking? Can you
have a delayed reaction, and are there any other long-term effects?

The psychiatrist: Robin Murray

The risk of smoking cannabis is a bit similar to that of drinking
alcohol. Most people who drink alcohol, and most people who smoke
cannabis, don't come to any harm. However, just as drinking a bottle
of whisky a day is more of a hazard to your health than drinking a
pint of lager, so skunk is more hazardous than traditional forms of
cannabis, such as herb or resin, because it may contain three times as
much of the active ingredient tetrahydrocannabinol (THC).

The adverse effects of cannabis use are different to those you
describe. They usually start with either memory difficulties or
paranoid and suspicious ideas, and can progress to psychotic symptoms
such as hallucinations and delusions. These symptoms usually come on
while the individual is still smoking, and there is no good evidence
that smoking cannabis can cause either anxiety or insomnia.

. Professor Robin Murray works at the Institute of
Psychiatry

The nurse: Chris Hudson

It's unlikely that there's a direct link between your concerns and
your history of smoking cannabis. While some insomnia and anxiety may
be a common experience for those who have recently given up using the
drug, there's little evidence to suggest these symptoms continue after
the body has eliminated it from the system - which is between four to
six weeks in the case of cannabis. Your complaints could be caused by
stress, side-effects from prescription drugs, alcohol use or exposure
to allergens.

Recent reports on the damage to lungs caused by smoking cannabis -
that one joint can be equal to five cigarettes - are probably true,
though it's not helpful to get hung up on numbers. The good news is
that even after five years, your lungs and other organs have made much
progress in repairing damaged tissue. Your GP will be able to
recommend strategies for managing the anxiety and insomnia.

. Chris Hudson is a nurse and operations manager at Respond, the drug
treatment centre

The consultant: Dr Ken Checinski

Evidence suggests a delayed reaction is unlikely. However, cannabis -
especially skunk - can lead to acute and severe psychotic episodes
(including believing strange, often fearful things and seeing or
hearing things that aren't there), or trigger an underlying
vulnerability to mental illness, most typically in cases of
schizophrenia.

When long-term users stop taking a drug, it's quite common to replace
it with something else. Are you substituting cannabis with alcohol or
other drugs? Substances like these may mask underlying problems such
as depression or anxiety.

Your symptoms may be a response to everyday stresses and are likely to
get better on their own or respond to psychological treatments
available through your GP. Don't self-medicate and resist any
temptation to start using cannabis again in order to relax.

For more information, visit the mental illness charity Rethink at
www.rethink.org

. Dr Ken Checinski is a senior consultant in addictive behaviour