Psychosis: Do they know it's drug-induced?

Mental Health Nursing,  Mar 2003  by Cooper, Phil

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Guidance from the Department of Health (2002) regarding dual diagnosis has recently been issued. This study by Phil Cooper explores the attitudes of psychiatric nursing staff towards illicit drug use via the use of a drug attitude scale. Interviews also took place with a sample of these psychiatric nurses to examine their views of the diagnosis of drug-induced psychosis. Among the results, it was found that many psychiatric nurses are uncertain regarding aspects of illicit drug use. Older nurses viewed drug taking as a less positive experience than younger nurses did and nurses at lower nursing grades had more negative views

In my practice as a community psychiatric nurse there appears to be an increase in a type of referral from psychiatric staff that intimates a person has a provisional diagnosis of 'query' drug-induced psychosis. Despite the use of the term 'query' as part of the provisional diagnosis, there is usually little information relating to the type of substance that is allegedly inducing the psychosis, an indication of the amounts of the drug being used or how the substance is ingested into the body.

Whether illicit substances are a causal agent in psychiatric disturbance remains a controversial area of debate (Hall and Degenhardt, 2000; Cunningham et al, 2000). Illicit drug sales are not monitored by any quality control body that could give an indication of how much any drug user has taken at any point in time. The result is that any personal estimate of the strength and amount of illicit drug used by someone is pure guesswork. Thus, it has been suggested that relying on self report data in descriptions of substance use can lead to under-diagnosis of substance related problems (Soyka, 2000; Cantwell et al, 1999).

Would different routes of ingestion (smoking, inhalation or injecting) mean differing amounts of a drug are ingested depending on how it gets into the system? There appears to be little objective information regarding how much illicit substance an individual has used. Finally, there may well be complications regarding treatment if a variety of illicit drugs are being used at one time (Poole and Brabbins, 1996).

Prevalence

There are wide variations in prevalence rates for dual-diagnosis in both the United States and the United Kingdom. The range can vary from 30 per cent to 65 per cent of studied populations admitted to psychiatric treatments that had a drug or alcohol problem (Khalsa et al 1991). Yet, why the wide variations?

One problem may be that there will be different methods of assessment for those admitted to, or presenting to, psychiatric services (Kanwischer and Hundley, 1990). Many people may not reveal the true extent of their illicit substance misuse (McPhillips et al, 1998). People may be too unwell on presentation to services to provide a full substance misuse history or professionals may have different views as to what constitutes a substance misuse disorder.

There are usually different study settings and demographic characteristics of samples that may account for such wide variations. Studies of people with a dual diagnosis are usually conducted at in-patient treatment centres. Certain studies (Regier et al, 1990) have alluded to phrases such as 'lifetime rates of psychiatric illness' which may imply that a psychiatric disorder happened during a person's lifetime, but may not be present at the time of the study. Some people may have a single episode of psychiatric problems while others have recurrent problems.

The timescale of a study may cloud the psychiatric diagnosis given. In other words, a person may require a period of abstinence from a drug over a few weeks before an accurate diagnosis can be made. Withdrawal states from certain drugs may mimic psychiatric illness, for example, depressive symptoms in early abstinence - but this does not indicate a major depression (Dorus and Senay, 1980).

When assessing people who present with psychiatric and substance misuse problems, there may be a lack of knowledge in this area (Poole and Brabbins, 1996). There may be confused ideas about which drugs may or may not cause psychiatric problems - for example, cannabis (Thornicroft, 1990; Mathers and Ghodse, 1992).

Great detail may not be recorded relating to the use of at least two or more mind-altering substances, for instance, alcohol and cannabis. Hammersley, et al, (1990) intimate that people who use alcohol and illicit substances may consume a variety of substances. The use of urinalysis tests are not consistent across services as a means of improving accuracy of any initial diagnosis. They are also expensive to use according to a report in The Lancet (Anonymous, 1987).

Attitudes to illicit substance misuse

People who present to services with co-morbid mental illness and substance misuse problems are, perhaps, one of the most stigmatised groups in society (Phillips, 1999). Attitudes of health professionals towards people with substance misuse problems are recognised as being crucial in the prevention of substance abuse. Also, diagnosis, treatment and rehabilitation are affected by a professional's attitude toward them and the stigma of that perceived problem (Byrne, 1997). McLaughlin and Long (1996) suggest that the majority of health professionals hold negative, stereotypical perceptions of illicit drug use. They further state that this may have produced very unsatisfactory and unsafe care, resulting in both client and carer being dissatisfied with the whole aspect of care.