A growing number of Japanese children are being prescribed psychotropic drugs to treat depression, attention deficit hyperactivity disorders (ADHD) and schizophrenia, according to a study by government-funded medical institutes.

In particular, the number of ADHD drug prescriptions for patients aged between 13 and 18 years old surged 2.49 times between two three-year periods covering 2002-2004 and 2008-2010, despite some of them being unapproved for use among children, the study said.

"Frankly, this is an unfortunate situation for the medical community" because doctors are having to take legal risks to provide some psychotropic drugs to underage patients, said Yasuyuki Okumura, a researcher at the Institute for Health Economics and Policy and co-author of the research paper.