Antipsychotic drugs are the most frequently prescribed of the psychotropic drugs among the intellectually disabled (ID) population. Given their widespread use, efforts to systematically assess and report side effects are warranted. Specific scaling methods such as the Matson Evaluation of Side Effects (MEDS), the Abnormal Inventory Movement Scale (AIMS), and Dyskinesia Identification System Condensed User Scale (DISCUS) are reviewed. Symptom patterns and a focus on additional research are discussed. While progress has been made, more and more systematic methods to research these problems are necessary.
Persons with intellectual disability (ID) are particularly vulnerable to a wide range of psychopathology such as schizophrenia, bipolar disorder, and anxiety (Coe et al., 1999, LoVullo and Matson, 2009, Matson et al., 1999 and Rose et al., 2009). Challenging behaviors such as aggression and self-injury are also more likely where ID is present, and existence of comorbid psychopathology further exacerbates challenging behaviors (Embregts et al., 2009, Giarelli et al., 2009, Lang et al., 2009 and Matson et al., 1997).
The existence of other disabilities such as co-occurring developmental disabilities of autism spectrum disorders or seizures is also much more likely to be seen in persons with ID (Dawson et al., 1998, Matson and Neal, 2009b and Matson et al., 2008a). All of these problems, which often overlap with ID put the individual at a particularly high risk for receiving one or more psychotropic medications. In fact, persons with ID tend to be the most overmedicated group in society (Matson and Boisjoli, 2009 and Matson and Neal, 2009a). Additionally, health issues, lack of coping, deficits in cognitive processing skills, and other concerns can make treating this population particularly challenging (Brown et al., 2009, Cheung and Siu, 2009, Matson et al., 2009a, Matson et al., 2009b, Nieuwenhuis-Mark, 2009, Shih et al., 2009 and Van der Molen et al., 2009). Psychotropic drugs, particularly antipsychotics, are considered an important treatment for many of these issues (deLeon, Greenlee, Barber, Sabaawi, & Singh, 2009).
Not only do persons with ID receive psychotropic medications at high rates, but these drugs tend to be prescribed for many years (Yen, Lin, Loh, Shih, & Hsu, 2009). A major risk factor of these prescription practices is the development of a host of side effects. The purpose of this review is to provide an overview of what we know with respect to the development of such side effects, and to point out areas for further research.
A number of papers have been published providing a rationale for the benefits of psychotropic medication use among persons with developmental disabilities (Santosh and Baird, 1999 and Valdovinos, 2007). It has been asserted, and we concur that in most instances neuroleptics, the most commonly prescribed psychotropic medications for persons with ID, are prescribed for their sedative effects rather than for specific antipsychotic effects (Gualtieri & Hawk, 1980). Having noted that, it is disappointing to see published state guidelines for psychotropic drug use that provide no advice on how to systematically evaluate these drug side effects (Suppes et al., 2005). However, there has been a general critical lack of systematic research on the potential short and long term side effects that these drugs produce. This is a major limitation in the evaluation of overall psychotropic drug effectiveness. Researchers have noted that 20–40% of people with ID are prescribed psychotropic medications, which is a startling admission (Deb, 2006). These rates are even higher where these people are routinely receiving professional care (Holden & Gitlesen, 2004).
There is also the issue of drug effectiveness, particularly where challenging behaviors are involved (Matson & Wilkins, 2008). Ahmed et al. (2000) withdrew the antipsychotic medications of 36 adults with ID, of which only 19 (52%) fully completed medication discontinuation. The authors compared the withdrawal completers on measures of side effects and challenging behaviors to a control group. Out of the 19 participants who completed the withdrawal group, there was no difference between the withdrawal and control group on challenging behaviors. This study, along with a number of other studies, put the effectiveness of psychotropic medications into question for challenging behaviors. This fact and the potential and often unknown long term side effect profiles of these drugs led us to question whether such drug practices can be justified.
Unfortunately, the realization that much of the psychotropic medication research is methodologically flawed, that reliable instruments to evaluate medication side effects should be in place, and the notion that psychotropic medication in general and antipsychotics in particular are not well established as efficacious for challenging behaviors are not new. Gualtieri et al. (1986) made many of these same observations almost 25 years ago. Little progress has been made, and a small percentage of published studies have systematically addressed these issues of efficacy on side effects in the literature.
