Marijuana use and psychiatric illness

In recent months, media coverage of marijuana has focused on the benefits of cannabis and the debate over de-criminalizing the herb. I thought this week's column would be an appropriate place to outline some of the less widely discussed effects the drug can have on psychiatric conditions.

While cannabis may be useful to a select group of people suffering from terminal illness or chronic pain, there are also drawbacks to nature's drug.

Not only does current drug use of any kind make the diagnosis of existing psychiatric conditions impossible, in many cases, the use of marijuana can have adverse effects on the management, treatment and experience of known psychiatric disorders.

Marijuana use is a common problem among those suffering from Attention Deficit/Hyperactivity Disorder (ADD/ADHD). Young people with this disorder are already impulsive and are more likely to experiment or use drugs regularly. Although they often tell me that the drug is helping them, it is usually in the sense of mellowing them out or making them less concerned about their problems rather than improving their cognitive functioning.

Marijuana use can cause serious complications in memory, attention and organization, all of which are a problem for ADD/ADHD sufferers. Those with the disorder already struggle in these areas and compound their problem when they use marijuana. Unfortunately, even when drug use is stopped, cognitive impairment can persist for up to six months.

Use of drugs such as cannabis can be both a cause and consequence of emotional problems. For example, mood disorders such as depression and bipolar disorder can become worse with the use of cannabis. Often, people take the drug because they think it will make their symptoms of depression go away, but this is not wise as marijuana can make symptoms worse or even trigger them. In the case of bipolar disorder, the use of marijuana can cause the person to shift from one mood state to another, which is exactly what treatment is attempting to stop.

Anxiety is another unsettling side effect of cannabis use. Again, people often use drugs to alleviate anxiety or make themselves 'feel better', but this can actually make anxiety worse and can trigger panic attacks or episodes of anxiety in a person who has not experienced them before. It is not uncommon for my patients to report the initial onset of panic attacks with canabis use. This is so frightening that they almost always stop immediately.

A significant amount of evidence has emerged in recent years that marijuana can produce psychotic episodes during which the person experiences confusion, amnesia, delusions, hallucinations, anxiety, agitation and manic symptoms. While psychotic symptoms usually abate quickly after drug use is stopped, there is also strong evidence that marijuana use can trigger schizophrenia in vulnerable individuals. This is not a short-term problem.

Another symptom of regular cannabis use that is often debated is 'amotivational syndrome'. This syndrome refers to symptoms of apathy, loss of effectiveness, diminished capacity or willingness to carry out long-term plans, endure frustration, concentrate for long periods, follow routines or successfully master new material.

These symptoms are not desirable for anyone, but can be particularly harmful to someone who already suffers from a psychiatric condition. For example, many of these symptoms are already a problem for a person with ADD/ADHD and are compounded with drug use. Also, a depressed patient often feels as though it is useless to participate in activities or carry out plans and it is even harder to cope when the person is also a regular cannabis user.

While some people may benefit from marijuana for certain specific conditions, the evidence from controlled clinical trials for both risks and benefits of cannabis is not yet up to the usual standard for prescription drugs. The reality is that for most individuals, regular drug use is incompatible with a life of meaningful relationships, productivity and satisfaction. In particular, those who suffer from a psychiatric disorder should avoid substances such as cannabis.


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