Treatments for ASD: how do we develop better evidence?
Staff blogger Nancy Jones, Ph.D., Program Director for the Autism Treatment Network and the Autism Clinical Trials Network
Finding evidence-based treatments is one of the greatest challenges for those seeking treatments for autism, particularly for those with complex or severe health issues. While support for behavioral treatments is robust, rigorous evidence for pharmacological and biomedical treatments is still needed. As individuals with ASD have different needs and different levels of symptom severity, it is critical to have a range of treatment options known to be reliably safe and effective. A report by the Cochrane Collaboration, released on Monday, reported on a comparative analysis of randomized controlled clinical trials conducted to date that examined the effectiveness and safety of various SSRIs (selective serotonin reuptake inhibitors) as treatments for core symptoms of autism and other associated symptoms. SSRIs have a long history of use as treatment for disorders such as depression, anxiety and obsessive compulsive disorder, and have been found in small studies and clinical use to be helpful for repetitive and compulsive behaviors in autism. Based on this recent analysis, the authors conclude that there currently is no evidence to support the use of SSRI’s for children with ASD and limited evidence for their use of as a treatment for adults with ASD.
What does this study mean for us now? Does this mean that we know for sure that SSRI’s don’t work at all for individuals with autism? With the evidence that we have to date, it may be premature to say we have definitive evidence to rule out the effectiveness of such treatments for some individuals with autism. It does suggest, as is stated in the report itself, that at this point, for the treating physician, that a decision to use on SSRI would need to be made on an individual basis. There are as of now only a few randomized controlled trials of SSRIs in children, five of which were reported on in the paper, and there have only been two large scale studies to date, the NIH-funded study of citalopram, which was included in the Cochrane review, and the Study of Fluoxetine in Autism, which was not included in the review. The five studies also were focused on different types of outcomes, making a harder to compare across the limited number of studies to determine relative effectiveness for the different outcomes.
The review does highlight some of the key challenges for doing treatment research in autism. One major challenge is dealing with the fact that individuals with ASD may manifest the core symptoms of autism, as well as associated symptoms,to different degrees and may suffer from different levels of symptom severity. In order to address the needs of this diverse population we will need to carefully consider how best to conduct research that will be comparing individuals with autism with the same types of symptom profiles. For example, both of the larger studies of SSRIs observed that children showed improvement over the course of the study, but level of improvement was not any better for the treatment group than the comparison (placebo) group. This means that the treatment may be effective for at least some subgroups of children. A recent presentation at IMFAR of additional analysis of the citalopram study, identified certain factors that may distinguish those who responded to the medication and those that did not. These may be significant in understanding treatment response.
Does this mean that we know for sure that SSRIs will work for everyone? No. But there may not be enough information now to say we have sufficiently determined for whom the SSRIs may work, for what type of autism symptoms and why. Future research needs to focus on identifying which subgroups of people with ASD respond to which medications.
It is important to continually provide families with the best evidence about treatments, so they can make informed decisions and have more treatment choices. Autism Speaks continues to support treatment research but is also launching new initiative to address the challenges faced in doing treatment trials and translating our basic science discoveries into to viable treatments. A major focus of this effort is to identify biomarkers that can help identify subgroups of individuals with ASD for whom specific treatments may be effective.
Williams K, et al “Selective serotonin reuptake inhibitors (SSRIs) for autism spectrum disorders” Cochrane Database of Syst Rev 2010; 8: CD004677.
For more about the Cochrane Collaboration: