The cannabis connection - looking for survey participants

cannabis graphic This survey has concluded. Thanks to all of those who participated.

The Psychosis and recreational drugs research group in the Psychology Department at Manchester Metropolitan University is looking for participants in a survey regarding the relationship between cannabis and psychosis.

The "Cannabis experiences questionnaire" takes about 15 minutes to complete. The following articles details the background of this survey.

Written by Rohan Morris and John Stirling (on behalf of the Recreational Drugs Research Group, Manchester Metropolitan University, UK)

Effects of cannabis

Records suggest that cannabis has been used both as a medicine, and for recreational purposes for many thousands of years. Medicinally, established beneficial effects include pain relief, reduced anxiety, and a marked reduction in the tendency to feel [or be] physically sick. Recreationally, cannabis induces a number of (pleasant) experiences ranging from mild elation to euphoria.

Unfortunately, the drug can also induce unpleasant effects; variously described as ‘aversive’ ‘negative’ and/or ‘dysphoric’. In some otherwise healthy individuals, cannabis (especially in larger quantities) induces a type of psychotic state that has been likened to acute schizophrenia; characterised by perceptual disturbances, delusions, unusual thinking and paranoia.

Although these changes are usually short-lived, there is increasing concern that some people are particularly sensitive to these ‘negative’ effects, and there is currently a debate as to whether cannabis can actually cause schizophrenia or other forms of long term (chronic) psychosis in such vulnerable individuals.

Cannabis and mental illness: cause or effect?

Cannabis is widely used by people with an existing diagnosis of schizophrenia or some related form of psychosis, and research has suggested that its use may lead to an increased risk of further relapses in a dose-dependent fashion; the more you use the more likely you are to experience further bouts of illness.

However, this does not necessarily mean cannabis causes schizophrenia per se: For example, it is possible that a young person who may go on to develop schizophrenia as an adult, is also more inclined to use cannabis, perhaps because of their personality, or as an expression of their openness to unusual experiences. It is also the case that some people with a history of psychotic illness say they use cannabis as a form of self-medication; or to counter the unpleasant effects of their conventional anti-psychotic meds.

In short, it is very difficult to produce conclusive scientific evidence that cannabis causes schizophrenia in people who otherwise would not develop it. All we can say at the moment is that some people appear to be particularly susceptible to the unpleasant effects of the drug, and perhaps that these individuals are at greater risk of subsequent illness, especially if they also have a predisposition to, or family history of, psychiatric disorder.

The effects of cannabis

Cannabis is a notoriously ‘dirty’ substance, typically containing over 70 psychoactive (mind-affecting) chemicals; the two main ones being THC and CBD. Recent research has shown that pure THC given to people with no history of mental illness can produce short-lived psychosis-like states.

THC increases dopamine release in the brain, and can exacerbate (make worse) some of the symptoms associated with schizophrenia. Incidentally, most anti-psychotic meds are thought to reduce symptoms by damping down the same dopamine system, and these meds also limit the ability of THC to induce psychotic-like states.

On the other hand CBD, which is the second most abundant chemical in cannabis, has been shown to relieve anxiety and improve mood, and there is even evidence that it may possess anti-psychotic properties. In other words, the two most abundant active components of cannabis appear to have opposite effects (which may explain the range of reported experiences, positive and negative, associated with its use).

Unfortunately, it is also the case that the chemical make up of cannabis has gradually changed in recent years. Varieties of high potency ‘skunk’, which contains proportionately more THC and less CBD have certainly become more popular, meaning that the type of cannabis most commonly used is potentially worse for a person’s mental health than was the case in the past. This has led some experts to predict a significant rise in the coming years, in the number of individuals seeking/requiring help for cannabis-induced (or cannabis-complicated) psychotic conditions.

We share these concerns, though our research on the psychological effects of cannabis, conducted over the past 7+ years on over 1000 non-clinical respondents, and reported in several scientific journals, has led us to the view that most people can use cannabis with little risk of mental breakdown.

However, a relatively small proportion of users, with a so-called ‘high schizotypy’ personality profile (characterised by a willingness to adopt irrational beliefs, susceptibility to perceptual disturbances and poor interpersonal social skills) are at increased risk of experiencing proportionately fewer positive and more negative effects of the drug. We believe that such individuals may, through continued use of cannabis, be putting themselves at increased risk of later mental illness.

Cannabis; your experiences and your health

About 2/3 of young adults have used, or currently use, cannabis. Yet only 1 or 2 in 100 develops a functional psychotic disorder. So we would need to follow-up a massive sample of people for many years in order to test our idea that particular cannabis experiences serve as ‘danger-signs’ of later mental health problems for a particular subset of ‘vulnerable’ individuals.

At the moment we simply do not have the necessary resources for such a project. However, an alternative approach is to record cannabis experiences in individuals who have/had mental health problems, and this is where you come in!

Essentially, we want to see if people with mental health problems, who have also used (and may continue to use) cannabis, have the same or similar reactions to the drug as people without a history of mental health problems, and if not, how their responses differ.

A very important outcome of our proposed research is the identification of cannabis-induced experiences that could predict increased proneness to subsequent psychosis in currently ‘healthy’ individuals, and your involvement in our study could help us achieve this goal!


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