(Medical Xpress)—The use of antidepressants doubled in Australia between 2000 and 2011 and they now account for two out of every three psychotropic medications prescribed, a new study by the University of Sydney reveals.

It also shows that over the last decade there has been a dramatic 58 percent increase in the use of psychotropic medications by the Australian population, which has only increased by 13 percent over that time.

"Australians are increasingly relying on the use of psychotropic meds to treat their ," said Professor Iain McGregor, from the University's School of Psychology and senior author of the study published this week in the Australian and New Zealand Journal of Psychiatry.

"These results are surprising, somewhat worrying, and raise the question of why so many of us need drugs to be able to cope with modern life.

"The heavy use of antidepressants may reflect their increasing use in conditions other than depression: everything from to treating pain.

"These drugs have been relentlessly promoted by the pharmaceutical industry but meds are not the only answer, and anyone with emotional problems should consider diet, exercise, and ," Professor McGregor said.

Psychotropic medications act on the brain and are used to control behaviour and mood. They are among the most widely prescribed drugs in Australia and worldwide. They include antidepressants, sedatives, antipsychotics, mood stabilisers and attention-deficit hyperactivity disorder medications.

The use of , commonly used to treat schizophrenia, has also doubled between 2000 and 2011.

"Use of in conditions other than schizophrenia, for example in bipolar disorder, depression, anxiety, ADHD and dementia, may be driving this increase," said Professor McGregor.

"While a godsend in many difficult cases, some of the antipsychotic drugs can have major side effects including obesity, diabetes and loss of interest in life."

The use of benzodiazapine drugs such as Valium has remained fairly static over the decade, although there has been a marked increase in the use of a drug called alprazolam or Xanax.

"This is of concern because Xanax can be highly addictive and is frequently overused," said Professor McGregor.

There has been a 73 percent increase in the distribution of medications used for ADHD, particularly the long-acting form of methylphenidate.

"The issue here is that there are concerns about the long-term effectiveness of these medications," said Professor McGregor.

Professor McGregor and his team are soon to publish a book, Meds for Heads, an exploration of psychotropic use in Australia.