Antipsychotic and other medications for autism: The state of the evidence

By Nestor Lopez-Duran PhD

Hi all! In the last post I started summarizing a series of studies that look at the scientific evidence for the effectiveness of specific treatments for symptoms of autism. I began by discussing research that suggests that Secretin is not an effective treatment for autism. This week Im discussing 3 additional medications (or classes of medications): antipsychotics (such as Risperidone), SSRIs (such as Prozac), and psychostimulants (such as Ritalin).

The effectiveness of these medications was recently reviewed in an article published in the Journal Pediatrics. The authors examined all previous studies that used good research methods to investigate whether these medications were effective in the treatment of some symptoms of autism. In addition, the authors were interested in determining whether the medications were safe.

Here is a summary of their results:

ANTIPSYCHOTICS:

Risperidone (Risperdal): The authors found 2 good randomized clinical trials (RTC) that compared Risperidone to a placebo (e.g., sugar pill) and 2 prospective studies that examined changes in challenging and repetitive behaviors after starting the medication. One of the studies was funded by the National Institutes of Health and the other was funded by the makers of the drug. In both studies, kids taking Risperidone improved significantly more than kids taking the sugar pill. Similar improvements were seen for hyperactive symptoms and repetitive behaviors. The authors concluded that evidence for the effectiveness of Risperidone in reducing challenging and repetitive behaviors was moderate. However, the was also significant evidence for adverse side effects including weight gain (an average of approximately 6 lbs. in 8 weeks), sedation, and some neurological symptoms.

Aripiprazole (Abilify): The authors found 2 good quality RTCs comparing Aripiprazole to placebos for the treatment of challenging and repetitive behaviors. In both studies, kids taking Abilify improved significantly more than kids taking the sugar pill. The authors concluded that evidence for the effectiveness of Aripiprazole in reducing challenging and repetitive behaviors was High. However, the was also significant evidence for adverse effects including weight gain (an average of about 4 lbs. in 8 weeks), sedation, and some neurological symptoms.

SSRI (Selective Seretonin Reuptake Inhibitors):

Citalopram (Celexa): There was one good quality study comparing Citalopram to a placebo. There was no difference between kids taking Celexa and those taking the sugar pill in their levels of repetitive behaviors after 12 weeks of taking the medication. However, the levels of challenging behaviors decreased more among those taking Celexa than among those taking the placebo. Since there was only one study showing these trends and the results were modest, the authors concluded that at this time there was insufficient evidence for the effectiveness of this medication .

Fluoxetine (Prozac): There was one good quality RTC comparing Prozac to a placebo. Kids taking Prozac showed a larger decrease in repetitive behaviors than did kids taking the placebo. There were no major adverse side effects. It seems, therefore, that Prozac may be more effective than Celexa in treating repetitive behaviors.

PSYCHOSTIMULANTS:

Methylphenidate (Concerta, Ritalin): There was one good quality RTC comparing Methylphenidate to a placebo for the treatment of hyperactivity and non-compliance. Kids taking the medication improved significantly more than kids taking the placebo, but this was mostly at medium to high dosages (dosages ranged from 7.5 to 50 mg per day). However, some major side effects were reported including irritability (18% of those who quit the study did so because of irritability), sleep problems, anxiety, depression, and diarrhea.


What is most surprising about this comprehensive review is how little we actually know about the effectiveness and safety of these medications. We know most about Risperidone and Aripiprazole. Both of these medications appear to be effective although they have some severe side effects. The authors concluded that future research is unlikely to change these findings. However, we know significantly less about the effects of SSRIs and psychostimulants and we need much more research before we can determine conclusively whether these medications are effective and safe for the treatment of some symptoms of autism.

The reference:
McPheeters, M., Warren, Z., Sathe, N., Bruzek, J., Krishnaswami, S., Jerome, R., & Veenstra-VanderWeele, J. (2011). A Systematic Review of Medical Treatments for Children With Autism Spectrum Disorders PEDIATRICS, 127 (5) DOI: 10.1542/peds.2011-0427