A new Cochrane review finds no evidence to support the use of risperidone to treat attention- deficit/hyperactivity disorder (ADHD) in people with intellectual disabilities, even though the review authors say this is a common prescribing pattern.

Risperidone, or Risperdal, is a second-generation antipsychotic drug. Long-term use of these drugs is associated with serious side effects, including weight gain and increased risk for type 2 diabetes.

“People who have intellectual disability are more likely to receive treatment with second- generation antipsychotics for ADHD,” said lead review author Dr. Alex Thomson. “Doctors should be aware that there is no research to demonstrate the effectiveness of risperidone for ADHD in people with intellectual disability, and should carefully monitor each case and consider alternative treatments before trying risperidone.”

Laurel Leslie, M.D., an associate professor at Tufts University School of Medicine whose research centers on pediatric mental health, concurred: “This study demonstrates that we have a gap between what we’re doing clinically and what we have any research evidence for. It’s an important study, as it highlights the need for careful consideration of how we treat children’s mental health issues.” Leslie has no affiliation with the Cochrane review.

Thomson’s research group did not find one study that met their criteria for inclusion among more than 2,000 studies that they initially identified. The group analyzed 15 studies in depth, but ultimately rejected them all.

“Patients with intellectual disability and their families should be aware that without firm scientific evidence for risperidone’s effectiveness as a treatment for ADHD in this group, doctors can only prescribe on a case-by-case basis and such treatment should be regularly reviewed,” said Thomson, an academic clinical fellow with the Institute of Psychiatry at Kings College in London.

ADHD, one of childhood’s commonest psychiatric ills, fosters inattention, excess activity and impulsivity. An IQ below 70 with significant impairments in functioning is the criterion for intellectual or mental disability (formerly called mental retardation). Researchers estimate that at least 15 percent of people with severe intellectual disability also have ADHD.

Thomson and his colleagues searched all of the leading medical databases for randomized controlled trials, published and unpublished in any language, in which children or adults who had both an intellectual disability and ADHD underwent treatment with risperidone. They also contacted pharmaceutical companies and experts in the field for relevant studies, published and unpublished.

The researchers cite three previous studies, which indicated that among people with an intellectual disability, symptoms of ADHD are more common, serious and enduring than they are among people of normal intellect. Another earlier study suggested that ADHD symptoms are less responsive to medications in these patients, who might be more prone to side effects.

Leslie said it does not make sense clinically for a doctor to say categorically that when a child has ADHD, he is going to try Risperidone. However, she does acknowledge that, in some studies, risperidone has proven helpful in treating aggression, which is often a symptom associated with ADHD.

According to the Thomson and his coauthors, both ADHD and intellectual disability independently are associated with higher lifetime rates of psychiatric illness, such as major depression or bipolar disorder, and additionally in ADHD, anxiety and substance abuse disorders are more likely to occur.

“The message is not that risperidone should never be prescribed — we didn’t find positive evidence that it doesn’t work or is harmful — but that it should not be prescribed automatically and that it should be regularly reviewed,” Thomson said. “If it is effective for one individual, then it could be continued, but if it is not effective, it should be stopped and alternative treatments tried.”

For Leslie, “the take-home messages are: we need much more research specifically looking at the use psychopharmacological agents among children and, as clinicians, we need to be very careful to clarify the specific symptoms we are trying to treat and to understand why they are there before we make a diagnosis or prescribe any medication.”

The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions.

Thomas A, et al. Risperidone for attention-deficit hyperactivity disorder in people with intellectual disabilities. Cochrane Database of Systematic Reviews 2009, Issue 2

Source: Health Behavior News Service