Certain types of antipsychotic medication can cause children to put on weight—as much as 18 pounds—according to research appearing in the Journal of the American Medical Association.

Dr. Chrostoph Correll, MD, and associates observed 272 children aged 4 to 19 taking atypical antipsychotic medication for the first time. Drugs/Medications included olanzapine (Zyprexa), quetiapine (Seroquel), risperidone (Risperadol) and aripiprazole (Abilify)—drugs sometimes used to treat children with autism, schizophrenia or bipolar disorder.

Children’s weights were monitored over a 12-week period. During the last two weeks of the study, nearly all experienced significant weight gain. Average gain was as follows: 18.7 pounds with onanzapine, 13.7 pounds with quetiapine, 11.7 pounds with risperidone, and 9.7 pounds with aripiprazole. Children in the control group gained less than half a pound (.44 pounds) on average.

“(E)ffects such as age-inappropriate weight gain, obesity, hypertension, and lipid and glucose abnormalities are particularly problematic during development because they predict adult obesity, metabolic syndrome, cardiovascular morbidity, and malignancy,” authors of the study write.

Doctors were so concerned over weight gain in children taking onanzapine that they stopped treatment before the study was completed. “Each antipsychotic was associated with significantly increased fat mass and waist circumference,” authors write. “Altogether, 10 percent to 36 percent of patients transitioned to overweight or obese status within 11 weeks.”

As more children—some younger than 5-years-old—are diagnosed with bipolar and “disruptive behavior” disorders (such as ADHD), there is also a rise in atypical antipsychotic prescriptions. These medications are generally effective for children with autism and schizophrenia, but they may not be the best treatment for other conditions.

The authors suggest seeking alternative treatments. They write that, in view of the negative health outcomes, the benefits of using these medications “must be balanced against their cardiometabolic risks”, and say the results suggest including in prescription guidelines closer monitoring during the early months of treatment.

They also plan on researching whether or not diet restrictions and additional medications for weight and glucose control will help balance the potential negative effects of the drugs.