Children taking widely prescribed psychiatric drugs gain significant amounts of weight, a study has found.

"Sometimes, this stuff just happens like an explosion. You can actually see them grow between appointments," Dr. Christopher Varley, a psychiatrist with Seattle Children's Hospital, told The Associated Press.

Varley called the study "sobering."

The study published in Wednesday's Journal of the American Medical Association found that every one of the more than 200 children and adolescents who took the medicines in the study added weight.

Weight gain is a known possible side effect of the anti-psychotic drugs, which are prescribed for various problems such as bipolar disorder and autism.

The study also linked some of these drugs with increases in blood fats, including cholesterol.

Researchers worry that these increases in weight and blood fats may make children more prone to heart problems in adulthood.