Home > Schizophrenia Explained > Drug abuse does not cause schizophrenia
Drug abuse does not cause schizophrenia
Hallucinogenic drugs like LSD can induce short-lasting episodes of psychosis and the heavy use of marijuana and stimulant drugs like cocaine and amphetamines may precipitate brief, toxic psychoses with features similar to schizophrenia. It is also possible, though by no means certain, that drug abuse can trigger the onset of schizophrenia.
Relatives of a person with schizophrenia sometimes blame hallucinogenic drugs for causing the illness, but they are mistaken. We know this because, in the 1950s and 1960s, LSD was used as an experimental drug in psychiatry in Britain and America. The proportion of these volunteers and patients who developed a long-lasting psychosis like schizophrenia was scarcely greater than in the general population. It is true that a Swedish study found that army conscripts who used marijuana heavily were six times more likely to develop schizophrenia later in life, but this was probably because those people who were destined to develop schizophrenia were more likely to use marijuana as a way to cope with the pre-morbid symptoms of the illness.
Do people with schizophrenia use more substances?
It seems to be true that people with schizophrenia use more drugs than others in the population. In one large study of mental disorder carried out in several American cities, the Epidemiologic Catchment Area (ECA) study, the prevalence of substance abuse at some time in the person's life was as high as 47 per cent of people with schizophrenia, compared to 17 per cent of people in the general population. Similarly current substance abuse rates in different samples of Americans with schizophrenia, running at 30 to 40 per cent are substantially higher than the ECA rate or 15 per cent
There is less agreement, however, about which drugs tend to be used more by people with schizophrenia. Two different reviews of the literature concluded that people with schizophrenia tend to use hallucinogens and stimulants (like amphetamines and cocaine) more than do people in the general population, but they disagree about whether marijuana use is greater. Both reviews conclude that the use of alcohol, sedatives and narcotics is no greater among people with schizophrenia.
The Environment of Schizophrenia
Brunner-Routledge 2000
Richard Warner
