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What is the value of combination therapies in autism?

April 26, 2010 3 comments

This Top 10 Research Achievements of 2009 post comes from guest blogger Evdokia Anagnostou, M.D., a Clinician Scientist at Bloorview Research Institute and an Assistant Professor, Department of Pediatrics at the University of Toronto. Dr. Anagnostou leads a program of experimental therapeutics and neuroimaging in autism and is leading a series of clinical trials to study the efficacy of oxytocin, memantine, and other compounds for symptoms associated with autism.

The last decade has been fairly productive when it comes to research in psychopharmacology.    Large scale multicenter studies have been conducted and more than one medication has shown benefit for the treatment of symptoms associated with autism.    Still, our approach to pharmacology research has been relatively limited. We have examined the similarities between symptoms associated with autism and symptoms in other disorders, assumed  that similar symptoms across disorders have similar neurobiology, and “borrowed” medications from other disorders with “overlapping “ symptoms to test in autism.  The approach has been somewhat successful.  We now have evidence from large multisite studies to support the efficacy of some atypical antipsychotics for irritability and aggression (risperidone (1) and aripiprazole (2)), and stimulants for the treatment of ADHD-like symptoms (3).  This approach also has its limitations.  An example may be the failure of large multisite studies to show effectiveness for the treatment of repetitive behaviors for serotonin re-uptake inhibitors (SSRIs). Although much remains to be explored and many questions still remain, one cannot help but wonder whether it is time for a paradigm shift in the way we approach pharmacology research.  There are plenty of approaches that still remain to be tested in this population.  Firstly, we have not yet done truly translational work.  In other words we have not yet used the findings from genetics/ animal models/ pathology to develop treatments based on the neurobiology of autism itself, as it is revealing itself to us over the past few years. Secondly, we have not addressed what we really do in real life which is combine medications with psychosocial interventions.  In fact, we have no data to date that any of the medications we use actually treat autism. Medications do not teach skills. It is the psychosocial interventions that treat autism.  What we attempt to do with medications for the most part, is to enhance learning from such interventions either indirectly by reducing behaviors that interfere with learning ( e.g. irritability, aggression, hyperactivity, repetitive behaviors) or by directly facilitating learning processes (potential examples in trials: memantine, oxytocin).  The question remains whether the combination of medications with psychoeducational treatment is favorable compared to medications alone or the psychoeducational treatment alone. Previous studies in other neurodevelopmental disorders, such as ADHD, (4) have taught us that when the effect of medication is large, it may be hard to show additional benefit from psychosocial interventions.  As such both comparisons: combination treatment vs. medication, and combination treatment vs. psychosocial intervention are worth exploring.

Recently, the RUPP group published the first randomized controlled trial that tested the combination of a medication with a parent training curriculum based on ABA principles for the treatment of irritability/aggression (link to Top 10 story on combination therapy) (5).   This was a 24 week randomized trial of combination treatment vs. medication only (risperidone/aripiprazole alone).  124 children ages 4-13 with frequent aggression, self injury and tantrums were recruited.  The primary outcome measure was a modified for autism version of the Home Situations Questionnaire (HSQ), a 20 item questionnaire aimed to measure non compliance in every day circumstances. Secondary measures included the Aberrant Behavior checklist, the Clinical Global Impressions measure and the Children Yale Brown Obsessive – Compulsive Scale-PDD version.  The parent intervention consisted of 11 sessions with a certified therapist, three additional optional sessions and up to 3 booster session for a total of up to 17 sessions, lasting 60-90 min and delivered individually to the families. The curriculum included teaching on visual schedules, positive reinforcement, compliance, functional communication and adaptive skills.  The sessions were fairly individualized to the child’s level and needs. The medication was risperidone dosed by weight and was switched to aripiprazole by week 8 if the risperidone was ineffective.  The study reported that combination treatment was more effective than medication alone as measured by the HSQ, irritability hyperactivity and stereotyped speech as measured by the ABC. They also reported that the mean dose of medication required in the combination group was less than that required in the medication alone group (1.98 mg/d vs. 2.26 mg / day respectively).

In summary, combination treatment was more effective at improving everyday outcomes than medication treatment alone.  This Top 10 paper provides initial evidence that such trials are feasible and worth exploring. The authors argued that this study aimed at a different outcome (real life situation improvement) than the original risperidone studies, and as such, suggests that integrated trials can be successful when the outcome measure for the medication is somewhat different than that for the psychosocial intervention / combination treatment.   In fact, as previously discussed, it makes sense that generalizability of the medication effect is accomplished by parent training given that the medication itself is not likely to teach the child or the family any skills.  The question still remains in the blogger’s mind whether the effects of combination treatment should be tested against intensive parent training alone. Although I agree with the authors that the effect size of the risperidone is large, these medications are associated with a relatively unfavorable side effect profile and it would be of great interest to learn how much of the effect size observed with the combination treatment can be achieved by using parent training alone, given that decisions on the using a medication are not solely based on the efficacy profile of medications. Such studies may have implications for systems delivery and the generalization of results may be more difficult given the differential insurance coverage for medications vs. psychosocial interventions, but may have significant impact in the way we treat children with autism

The study is very important as it is the first such trial in autism and highlights the need for integrated medication/psychosocial intervention trials. Future studies will likely focus on integrated treatments targeting both decrease of maladaptive behaviors as well as skills acquisition.

1. Research Units on Pediatric Psychopharmacology Autism Network. Risperidone in children with autism and serious behavior problems. N Engl J Med. 2002;347:314Y321.

2. Owen R, Sikich L, Marcus RN, Corey-Lisle P, Manos G, McQuade RD, Carson WH, Findling RL. Aripiprazole in the treatment of irritability in children and adolescents with autistic disorder. Pediatrics. 2009 Dec;124(6):1533-40.

3. Research Units on Pediatric Psychopharmacology Autism Network. Randomized, controlled, crossover trial of methylphenidate in pervasive developmental disorders with hyperactivity. Arch Gen Psychiatry. 2005 Nov;62(11):1266-74.

4. MTA Cooperative Group. National Institute of Mental Health Multimodal Treatment Study of ADHD follow-up: 24-month outcomes of treatment strategies for attention-deficit/hyperactivity disorder. Pediatrics. 2004 Apr;113(4):754-61.

5. Aman MG, McDougle CJ, Scahill L, Handen B, Arnold LE, Johnson C, Stigler KA, Bearss K, Butter E, Swiezy NB, Sukhodolsky DD, Ramadan Y, Pozdol SL, Nikolov R, Lecavalier L, Kohn AE, Koenig K, Hollway JA, Korzekwa P, Gavaletz A, Mulick JA, Hall KL, Dziura J, Ritz L, Trollinger S, Yu S, Vitiello B, Wagner A; the Research Units on Pediatric Psychopharmacology Autism Network. Medication and Parent Training in Children With Pervasive Developmental Disorders and Serious Behavior  Problems: Results From a Randomized Clinical Trial. J Am Acad Child Adolesc Psychiatry. 2009 Oct 23. [Epub ahead of print]

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