Author
DUGGAN L.; BRYLEWSKI J.;
Title
Antipsychotic medication versus placebo for people with both schizophrenia and learning disability (review).
Journal citation/publication details
Chichester: John Wiley and Sons; Cochrane Collaboration, 2004. 14p.Summary
This updated review identified only one relevant randomised controlled trial (RCT), and this was excluded because it provided data for only two of the four participants. Excluded studies are listed, however, and the review provides a summary of issues relating to the treatment of this group of patients.
Context
Antipsychotic medication is very widely used for people with a dual diagnosis of mental illnesses and learning disability, but there is conflicting opinion about whether such patients may be at higher risk than non-learning disabled people of developing unpleasant side-effects.
Methods
What sources were used?
The Cochrane Schizophrenia Group trials register (July 2004) was searched, together with the reference lists of relevant studies. Data were also sought from pharmaceutical companies. The sources used for two previous versions of the review were the Group’s register and the National Research Register (2001 version) and Biological Abstracts, the Cochrane Library, EMBASE (Excerpta Medica), Medline and PsycLIT (1999 version).
What search terms/strategies were used?
Search strategies for all versions of the review are given in full.
What criteria were used to decide on which studies to include?
Eligible studies were RCTs involving adults over 18 with both schizophrenia and learning disability (defined as an IQ of 70 or less) in which any type of antipsychotic medication delivered for one month was compared with placebo.
Who decided on their relevance and quality?
The searches delivered 28 references which were screened independently by the authors, with disagreements resolved by discussion. The trials were graded for quality according to the guidance in the Cochrane Handbook
How many studies were included and where were they from?
All 28 trials were excluded. Eighteen were not randomised, four were not placebo-controlled and others included participants without schizophrenia and/or learning disabilities. One 1958 trial involving four people fulfilled the inclusion criteria but provided insufficient data to draw meaningful conclusions.
How were the study findings combined?
Not applicable.
Findings of the review
The limited number of trials – of whatever quality – identified for this review is of great concern, especially given the use of quite liberal inclusion criteria. Other studies suggest that the underlying neurological damage present in people with learning disabilities may render them more likely to develop additional problems as a result of taking antipsychotic medication. These may include irreversible movement disorders such as restlessness, abnormal movements of the face, mouth, shoulders and trunk, tremor and disturbances of expression and gait. In addition, there is some suggestion that there may be detrimental effects on learning and cognitive abilities. The authors also note that antipsychotic medication is widely used for its tranquillising effects in people who are learning disabled but not mentally ill.
Authors' conclusions
There is no good quality evidence to answer the review question.
Implications for policy or practice
At present the prescribing of anti-psychotic medication to this patient group is based on extrapolation from National Institute for Clinical Excellence (NICE) guidance which in turn is based on research evidence from the non-learning disabled population. This ‘may be considered unethical’. Clinicians should continue to follow NICE guidance but ‘should share their uncertainty with service users and their carers’. While it is understandable that researchers are often reluctant to work in this difficult area, it is essential that research funders take action on the evidence gap and ‘we feel that those with a learning disability and schizophrenia together with their families should help address this shortfall.’