An Australian-led review of a popular anti-depressant drug has found it can tip young people into suicide and is no more effective than a placebo.

The research team also uncovered evidence that the drug's manufacturer downplayed its deadly side-effects and exaggerated its benefits.

The study, published in the British Medical Journal, reviewed data used by pharmaceutical companies to help market the drug, which is sold in Australia under the names Aropax and Paxil. It is also known as paroxetine.

Clinicians prescribed billions of the pills during the 1980s and '90s, when it was widely regarded as highly effective at treating depression without many of the debilitating side-effects of earlier medications.

Key points: Review finds anti-depressant may actually be dangerous for mental health

Review finds anti-depressant may actually be dangerous for mental health Also finds benefits of drug were exaggerated

Also finds benefits of drug were exaggerated Company that originally marketed drug denies failing to cooperate with review

But a few decades on, a review of data used to support paroxetine has found that confidence in the drug was misplaced and dangerously overstated.

"We felt that bad prescribing decisions were being made on the basis of the way in which the study was reported," said Professor Jon Jureidini, who led the international team of researchers from Adelaide University's Critical and Ethical Mental Health Research Group.

"The study claimed to show that paroxetine, an anti-depressant, was effective and safe for young people and in fact, it's the opposite."

The team have established that the drug carried twice the level of severe adverse effects across the board, and four times the number of psychiatric adverse events.

"Eleven patients experienced suicidal behaviour or self-harm out of less than 100 in the paroxetine group compared to just one in the placebo group," he said.

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Professor Jureidini emphasised his review should not cause people currently prescribed paroxetine to stop taking their medication unless directed to do so by their doctor.

But he said doctors should approach use of the drug more sceptically.

"It is not a cause for panic but it is a cause for taking greater care in prescribing," he said.

Researchers say drug approval system is broken

Professor Jureidini's damning reassessment comes after the review team reanalysed data that had originally been gathered during studies from 1994 to 1998 and was published in 2001 by the drug's manufacturer, pharmaceutical giant GlaxoSmithKline.

The data had been used to support papers published in scientific journals at the time recommending the efficacy and safety of paroxetine.

But Professor Jureidini's reassessment of the same data has produced markedly different conclusions.

He said the conflicting outcomes demonstrates the system of researching and approving new drugs that is fundamentally broken.

Professor Jureidini said he learned some important lessons from his research.

"One is that in order to be confident of the integrity of the way in which a study is reported, you need to have access to the original protocol, the guidelines that are written before the study is carried out in order to check whether they've been complied with," he said.

"And you also need access to individual level data, data collected at the site of the studies, so that you can check that the harms being experienced by patients have been properly documented and counted."

Professor Jureidini said it was also "extremely difficult" to obtain the data from GlaxoSmithKline.

Paroxetine was originally marketed in Australia by GlaxoSmithKlin under the brand name Aropax, but the company no longer owns the product.

It denies failing to cooperate with the review, saying it made data about the drug available to the research team in the spirit of open disclosure.

Company defends checks and balances

The company's communications director, Bernadette Murdoch, told The World Today "we did provide an unprecedented level of data to the research team".

"It is not an easy process," she said.

"These studies were conducted in the '90s, many years ago when computer systems were very different. A lot of the notes were handwritten but we did provide all of the data that was requested by the team so that they could carry out the reanalysis."

Ms Murdoch said it was important to remember that "when a medicine is approved for use, it's not just the pharmaceutical company that makes that decision".

"There are lots of checks and balances in between, so a regulator uses all of the data that's available on a medicine before recommending it for use for a patient," she said.

"In relation to the findings from the team's analysis, they do appear to be in line with the longstanding view that these medicines, anti-depressants like paraxetine, are not suitable for children.

"This is widely known and clear warnings have been placed on the product label for more than a decade."

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