A new study shows that a combination of stimulant and an antipsychotic drug could help reduce symptoms of attention-deficit/hyperactivity disorder (ADHD) and aggression.

Researchers at the Ohio State University Wexner Medical Center also said that along with the combination therapy, parents need to be taught behavior management techniques, which could help them control aggression in kids.

The study is published in the Journal of the American Academy of Child and Adolescent Psychiatry.

ADHD or Attention-Deficit / Hyperactivity Disorder is characterized by the inability to pay attention and control behavior and being overtly active. The condition is rapidly increasing in the U.S., with one out of every ten children showing symptoms of ADHD. Currently, there is no cure for the condition, but it can be successfully controlled through medication and behavioral therapy.

One hundred and sixty eight children between ages 6 and 12 participated in the study. All the children had been diagnosed with ADHD and had displayed severe physical aggression. All the participants were given a psychostimulant drug called OROS methylphenidate and the parents of these children were put on training for nine weeks. Researchers called this group the 'basic group' because both the treatments are known to reduce aggression.

The team wanted to know if they could improve this treatment. They added a second drug after three weeks of therapy; the control group got a placebo while the test group got an antipsychotic drug risperidone.

Researchers found that kids on the drug-combo got better scores on "Nisonger Child Behavior Rating Form (NCBRF) Disruptive-Total Scale, the NCBRF Social Competence subscale and the Reactive Aggression part of the Antisocial Behavior Scale," than children who just got the psychostimulant.

Also, the team found that kids who got two drugs instead of one had fewer side-effects than children who were put on one drug.

"Combination pharmacotherapy is becoming common in child and adolescent psychiatry, but there has been little research evaluating it," said Michael Aman, director of clinical trials at Ohio State's Nisonger Center and emeritus professor of psychology, first author of the study, according to a news release. "Our findings may be considered somewhat controversial because they appear to support the use of two drugs over one for treating children with aggression and disruptive behavior when things do not seem to be going well. Many practitioners have been taught to 'Keep things simple and safe' in their medical training. In general, this is good advice."