Elsevier

Research in Autism Spectrum Disorders

Volume 6, Issue 3, July–September 2012, Pages 1142-1149
Research in Autism Spectrum Disorders

Polypharmacy profiles and predictors among adults with autism spectrum disorders

https://doi.org/10.1016/j.rasd.2012.03.005Get rights and content

Abstract

Pharmacological interventions are frequently used to treat commonly associated mental health and behavioural issues in individuals with autism spectrum disorders (ASD). Despite high rates of psychotropic drug use documented in children with ASD, very few studies have examined medication profiles, side effects, and rates of polypharmacy in adolescents and adults with ASD. To address this, we examined medication profiles and predictors of polypharmacy among 142 adults with ASD who had experienced a psychiatric crisis. Of the 142 adults sampled, 91 (64.1%) were prescribed at least 1 psychotropic medication and 41 (28.9%) were taking 3 or more psychotropic medications. Variables associated with and predictive of polypharmacy included history of aggression, residence, and psychiatric support. Adults with ASD are a highly medicated population and polypharmacy is a significant concern in this vulnerable group of individuals.

Highlights

► Among a cohort of adults with ASD and clinical issues, 46.5% adults were taking two or more psychotropic medications and 28.9% 3 or more psychotropic medications. ► Psychiatric support, residence, and history of aggression were significant predictors of polypharmacy in adults with ASD. ► Over one quarter of adults with ASD prescribed psychotropic medications were not receiving any additional clinical support aside from psychiatry.

Introduction

Mental health and behavioural issues are extremely common in individuals with autism spectrum disorders (ASD) and the primary treatment for these issues is pharmacological (Kwok, 2003, Matson and Dempsey, 2008, Matson and Hess, 2011, McDougle et al., 1996). As a result, individuals with ASD are a highly medicated population (Kerbeshian et al., 2001, Kwok, 2003, Martin et al., 1999, Matson and Hess, 2011, Myers, 2007, Santosh and Baird, 2001). Although there is no drug identified to treat the core deficits of autism (Aman and Langworthy, 2000, Broadstock et al., 2007, Kwok, 2003, Myers, 2007), pharmacological therapies are frequently used to treat associated behavioural or psychiatric symptoms (Kwok, 2003, Lescovec et al., 2008, Martin et al., 1999, Myers, 2007, Posey et al., 2006). Several published double blind placebo controlled drug trials have been conducted among adolescents and adults with autism (Hollander et al., 2005, McDougle et al., 1998a, 1996; Remington, Sloman, Konstantareas, Parker, & Gow, 2001), along with some open label trials (Brodkin et al., 1997, McDougle et al., 1998b) and case series (McDougle, Kem, & Posey, 2002). Whilst there may be situations where medication use is clinically indicated or warranted, polypharmacy, defined in this study as the use of two or more psychotropic drugs in the same individual, is a growing concern (Matson & Hess, 2011).

Literature on predictors of psychotropic medication use and ASD is limited, with most studies focused on children (Mandell et al., 2008, Oswald and Sonenklar, 2007, Rosenberg et al., 2010), and fewer studies including children, adolescents and adults (Aman et al., 2003, Aman et al., 2005, Aman et al., 1995, Langworthy-Lam et al., 2002, Martin et al., 1999, Witwer and Lecavalier, 2005). This is particularly concerning given our knowledge that adults with ASD are more likely to be medicated and more likely to be on multiple medications than children with ASD (Aman et al., 2003, Aman et al., 2005, Aman et al., 1995, Mandell et al., 2008, Seltzer et al., 2004). Greater age, along with more restrictive housing and more severe autism are all associated with increased medication use (Aman et al., 2003, Aman et al., 2005). The aim of the current study, therefore, is to examine medication profiles and risk factors for polypharmacy among adults with ASD.

To date, there are only four reports on psychotropic medication use focused exclusively on older adolescents and adults with ASD. One of these studies, conducted in the US by Esbensen, Greenberg, Seltzer, and Aman (2009), used parent data to study the longitudinal use of psychotropic and nonpsychotropic medication over a 4.5 year period. Results found that the proportion of individuals taking psychotropic and non-psychotropic medications increased over time as did the number of medications taken (Esbensen et al., 2009). At time one, 71% of participants reported taking at least one medication and 24.5% taking three or more. At time two, rates increased to 81% for one medication and 40.6% for three or more. In 2007, Tsakanikos, Costello, Holt, Sturmey, and Bouras examined psychotropic medication use among a group of 66 adults with ASD and intellectual disability (ID) in an outpatient psychiatric service in the UK. They reported that outpatients with ASD and ID were more likely to be prescribed antipsychotics compared to controls matched on age, gender and IQ, and that physical aggression and pestering staff/others predicted antipsychotic use. Similar results were observed in the 2008–2009 National Core Indicators Consumer Survey Report (National Core Indicators Program, 2009) based on a representative sample of adults with ASD (N = 1128) and without ASD (N = 9501) across the US. Adults with ASD were more likely to be taking medication for mood, anxiety, behaviour and psychotic disorders than adults without ASD, but less likely to have a psychiatric diagnosis. In another UK based study, Morgan, Roy, and Chance (2003) examined medication use and rates of psychiatric illness among 164 adults with autism and ID in an outpatient psychiatric service. In this sample, 52% of adults were prescribed psychotropic medication and 40% of those prescribed medication had no other psychiatric diagnosis in addition to autism.

Together, these studies suggest that psychotropic medication use is common in adults with ASD, but studies remain difficult to compare. The two American studies were community based and the remaining UK studies were clinic-based. None of these studies compared medication patterns according to residential setting despite research conducted by Aman et al., 2003, Aman et al., 2005, Aman et al., 1995, primarily focused on younger individuals with ASD, suggesting a relationship between medication use and residence type. Furthermore, rates of medication use were categorized differently across the four studies, with Esbensen et al. (2009) studying rates of polypharmacy for psychotropic and non-psychotropic medications, and the remaining reports examining which medication classes were prescribed, but not how many. No studies examined how medication use related to the use of other types of interventions.

To address these gaps, the current study examines medication profiles and predictors of polypharmacy among adults with ASD living independently or with family, and in group home settings. Rather than focusing exclusively on clinic or community based samples, this study focuses on adults with ASD presenting with clinical issues, but not necessarily receiving clinical services. Generally, this study aims to replicate the limited research in this area and to extend previous work by considering the relationship between a series of clinical and demographic variables and polypharmacy. We predicted that polypharmacy would occur for a significant proportion of adults with ASD who presented with a clinical issue, and that those in higher need settings would be most likely to be medicated (Aman et al., 2003, Aman et al., 2005, Aman et al., 1995). We also hypothesized based on results of Tsakanikos et al. (2007), that one variable associated with high rates of medication use would be history of aggressive behaviour.

Section snippets

Methods

The analyses reported here are based on data from a larger project examining psychiatric crisis and developmental disabilities. For the purposes of this study, crisis was defined as “an acute disturbance of thought, mood, behaviour, or social relationship that requires immediate attention as defined by the individual, family, or community” (Allen, Forster, Zealberg, & Currier, 2002). Participants were recruited from one large and two medium sized urban centres in Ontario, Canada. At the time of

Participant characteristics

At the time of psychiatric crisis, 91 of 142 (64.1%) adults were taking at least 1 psychotropic medication. See Table 2 for breakdown of medication by class and Table 3 for breakdown according to number of medications. The most commonly prescribed medication was antipsychotic medication, and 41 (28.9%) individuals were prescribed 3 or more psychotropic medications.

A large proportion of adults who were prescribed psychotropic medications did not have an associated psychiatric diagnosis. For

Discussion

The present study examined medication profiles and predictors of polypharmacy in a sample of adults with ASD who had experienced a psychiatric crisis. Of the 142 adults sampled, 91 (64.1%) were prescribed at least 1 psychotropic medication, 66 (46.4%) were taking 2 or more psychotropic medications and 41 (28.9%) were taking 3 or more psychotropic medications. Polypharmacy is a significant concern in this vulnerable group of individuals with many adults prescribed psychotropic medications not

Acknowledgements

The authors thank the Canadian Institutes of Health Research (CIHR) for funding this research study (funding reference number 79539). This work was completed as part of a CIHR New Investigator Award to Dr. Lunsky. The authors thank the project scientists and staff as well as participating agencies for their involvement. They also thank Kousha Azimi for assistance.

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