ISSUES PERTAINING TO THE PRESCRIBING OF PSYCHOTROPIC MEDICATION FOR PERSONS WITH LEARNING DISABILITY: CURRENT PERSPECTIVES

Barry Coughlan reviews the literature on psychotropic prescribing for persons with learning disabilities.Barry J. Coughlan, Research Psychologist, Brothers of Charity Services, Bawnmore, Limerick

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The issue of the prescribing of psychotropic and psychoactive medication for persons with learning disability has been receiving increasing interest throughout the USA, UK and, more recently, in Ireland. According to Kalachnik (1988, 231), ‘psychotropic medication is prescribed for mentally retarded people primarily to suppress behaviour disorders (e.g. aggression, self-injury) or to alleviate the symptoms of mental illness (conditions such as psychosis or depression)’. For the purposes of the present paper, I aim to draw on recent research and theoretical perspectives on the issue of prescribing for persons with learning disability and how these impact on present-day practice. The current paper is based on a recent article in which I discussed psychopharmacology as a method of treatment in the learning-disabled population (Coughlan 2000).

In relation to the above quote from Kalachnik (1988), a number of points need to be made. Firstly, although psychotropic medication is frequently prescribed to persons with learning disability who display challenging behaviour, its effectiveness is poorly documented in the literature (Aman 1987; Wressell et al. 1990). Secondly, although many of those who display challenging behaviour may have an underlying mental illness, the magnitude of this effect is extremely difficult to ascertain. Thirdly, even if one accounts for those with ‘intractable’ behaviour disorders and the presence of an underlying mental illness, the prevalence of psychotropic prescribing should not be in excess of 20% (Singh et al. 1997).

Prevalence of psychotropic prescribing: the reality

From one of the first drug prevalence studies to be published, Lipman (1970) found an overall rate of psychotropic prescribing of 51%, and numerous reviews have since been published in the literature. The interested reader is referred to the work of Singh et al. (1997) and Rinck (1998). From the drug prevalence studies to date, overall figures tend to fall between 30% and 50% for psychotropic medications; 25-35% receive some form of anticonvulsant medication’ while the figure for psychoactive medication falls within the range of 50-70% (Aman and Singh 1988; Branford 1994). It is difficult to make comparisons across studies owing to problems of methodology and differing practices across countries, regions and indeed centres. On a positive note, however, one can see from the literature that the prevalence figures are decreasing with time; recent research shows that, with the implementation of medication monitoring procedures, effectiveness of prescribing, rather than prevalence per se, is taking centre stage.

Issues of concern

Four principal areas of contention or concern emerge almost consistently throughout the literature. The first is in relation to prevalence and in a sense the gross overmedication in the learning-disabled population as discussed above. A second issue is polypharmacy–the prescribing of two or more medications either from the same or from different drug categories. This practice is particularly evident in the prescribing of anticonvulsants for the control of seizures (Coughlan 1997) and in the prescribing of antipsychotic medication. Thirdly, quite frequently irrational prescribing practices are commonplace, with an inappropriate relationship between diagnosis (or suspected diagnosis) and the treatment regime. The fourth issue of contention is in relation to inadequate reviews of medication leading to unnecessary prolonged drug treatment (Fan 1991).

Psychopathology and learning disability (dual diagnosis)

Any discussion on prescribing should take into account the issue of psychopathology in the learning-disabled population. Dual diagnosis (the co-occurrence of a mental illness in conjunction with learning disability) (Reiss 1982) has received much attention in recent years largely owing to the process of de-institutionalisation and the principles of normalisation.

Although research has shown that learning-disabled people do exhibit the full range of mental health problems as in the general population (Eaton and Menolascino 1982; Reiss 1982), little information is available on the specific aetiology and prevalence of psychiatric and behaviour problems. Much of the research conducted has examined service users living in residential facilities or psychiatric clinics, and reported rates of psychopathology have therefore been elevated and are largely unrepresentative of the learning-disabled population in general.

The problem of terminology and definitions

Aside from the problems associated with classification, assessment and diagnosis of mental health problems in the learning-disabled population (Coughlan 1999), the issue of terminology and definitions continues to raise concerns, both in their epidemiological sense and in their practical sense. The inclusion of behaviour disorders in the definition of psychopathology might account for some of the variability in antipsychotic prescribing. However, Singh et al.‘s (1997) rule of thumb of not in excess of 20% clearly contradicts the findings of many studies, where prevalence rates have been well in excess of 20%.

Interestingly, there are no clear guidelines regarding the prescription of antipsychotics for behaviour disorder/challenging behaviour (or whatever terminology one might favour), and as a result many professionals in the field have expressed particular concern about this method of suppression of behaviour (Deb and Fraser 1994). As is noted by Aman and Singh (1991, 347) ‘in large measure, psychopharmacology in mental retardation has been directed more to suppression of non-specific symptoms than to matching known agents to well-defined syndromes as in adult psychiatry’.

On the other hand, if behaviour disorder is not included in the definition of psychopathology, then it is very difficult to account for the high rates of antipsychotic prescribing indicated in many studies. In such cases it is highly improbable that all clients being prescribed antipsychotics have an underlying mental illness, such as schizophrenia or psychosis. In this respect, Wright (1982) found a diagnosis of schizophrenia in 1.8% of the sample studied (1507 residents); affective disorder was diagnosed in 2.8%, while early childhood psychosis was diagnosed in 2.7%. Quite clearly the relationship between psychopathology and prescribing is as yet poorly understood and under-researched.

To sum up the appropriate use of psychotropic medication in relation to mental illness, Rivinus (1980, 195) states that ‘the same rules that apply to the use of psychotropic medications in adults and children of normal intelligence apply to retarded patients. Psychotropic drugs should be used to treat specific diagnoses, syndromes, or symptoms for which specific drug efficacy has been scientifically established’.

Challenging behaviour or mental illness ? The debate continues

To quote Moss (1999, 21), ‘the relationship between mental illness and challenging behaviour is as yet poorly understood, but there is some evidence that psychiatric disorders may, in some cases, underlie or exacerbate problematic behaviour’. Recent research on self-injurious behaviour and its association with an underlying obsessive-compulsive disorder supports this statement (King 1993; Bodfish et al. 1995). An approach gaining impetus at present examines challenging behaviour as an atypical presentation of an underlying mental illness, especially in those with severe learning disability (Emerson et al.1999).

Quite clearly the jury is still out at present and, based on the evidence to hand, will be for some time to come.

Medication monitoring procedures and medication review

As I mention in my recent paper (Coughlan 2000), there is a great need to review medication on a regular basis and for organisations to put in place a set of medication monitoring procedures or guidelines, in order to regulate the use of psychotropic medication. Such guidelines, however, should not come from just a single professional discipline: they should be multidisciplinary in nature and incorporate the expertise and views of all professionals working with persons with learning disability.

While these teams may have been developed as a direct response to the high level of psychotropic prescribing, their role is much broader. As Davis et al.et al (1998, 73) state, ‘teams do more than reduce inappropriate uses of psychoactive medication. They often improve the quality of the clinical information used to diagnose behaviour disorders and to prescribe medications .… a team approach using a broad range of input from all stakeholders–including the consumer, family, and staff–can provide a reliable, comprehensive, and data-orientated summary of the consumers behaviour’.

From the published research to date, there is no doubt that the implementation of such teams has a positive effect on the lives of those with learning disability, by means of rationalising the use of psychotropic medication. For further information and an excellent review of the current status of interdisciplinary teams, readers are referred to the work of Davis et al.(1998).

Conclusions and recommendations

Giving a brief review of the issue of psychotropic prescribing in the learning-disabled population is not an easy task, because the field of psychopharmacology incorporates many complex facets. In this respect what I have presented are some of the current issues and perspectives facing the field at the present time. Quality evidence-based research is continually required in order to make progress in this area that will impact on our practice for those with learning disability. It is my hope that by addressing these issues in the present paper will stimulate interest among professionals of all disciplines working with the learning-disabled population.

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