Antidepressants 'double suicide risk' says controversial study

"Antidepressants could double the risk of feelings that could lead to suicide, according to a new study which has triggered furious rows," The Daily Telegraph reports.

Critics have attacked the study as "fatally flawed" because researchers extrapolated certain side effects, such as anxiety, as being a risk factor for suicide.

Researchers carried out an analysis of 13 previous studies in healthy volunteers (people without depression) taking antidepressants to look for reports of side effects.

They wanted to see whether healthy volunteers taking SSRI and SNRI antidepressants, the most commonly prescribed types, were more likely to have feelings that could lead to suicide and violence.

These feelings, they said, included anxiety, agitation, shakiness and bad dreams.

They found people were 85% more likely to experience these sorts of feelings if they were taking antidepressants.

However, they didn't find any reports of people attempting suicide, thinking about suicide or being violent to others.

The study has been criticised by psychiatrists not so much for its findings, but for the way the researchers reported them.

"None of the included trials had a suicide or suicide-related event, but the paper talks incorrectly of risks of suicide," says Seena Fazel, Professor of Forensic Psychiatry and Wellcome Trust Senior Research Fellow at the University of Oxford.

If you're taking antidepressants and are worried about side effects, talk to your GP or psychiatrist about the balance of benefits and risks.

Never stop taking antidepressants suddenly, as this can make your symptoms worse.

Where did the story come from?

The study was carried out and funded by researchers from the Nordic Cochrane Centre, part of an international network of evidence-based medicine researchers. 

It was published in the peer-reviewed journal Royal Society of Medicine on an open access basis and is free to read online.

The Daily Telegraph carries a balanced and accurate report of the research and the controversy over the researchers' claims.

The Mail Online's coverage is basically accurate, although concerns about the events reported in the studies are only mentioned quite far down in the story.

The Sun reports that, "Antidepressants 'can make depressed people twice as likely to think about killing themselves'," which gets it wrong on both counts.

The research in the story did not include people with depression, and did not find any reports of people thinking about suicide.

What kind of research was this?

This was a systematic review and meta-analysis of randomised controlled trials (RCTs).

This is usually a reliable way to find out about the effects of a treatment. However, a meta-analysis is only as good as the studies included.

What did the research involve?

Researchers looked for published double-blind, randomised, placebo-controlled trials of selective serotonin reuptake inhibitors (SSRIs) and serotonin-noradrenaline reuptake inhibitors (SNRIs), two commonly prescribed antidepressants, in healthy adult volunteers, as well as unpublished clinical study reports sent to drug regulators.

They extracted information from the studies about adverse events that were either suicidal or violent, or considered to be "precursor events" to suicide or violence.

They carried out a meta-analysis to see whether these adverse events were more common in people taking antidepressants than placebo.

The researchers say they included adverse events "with particular focus on the list of criteria used by the Food and Drug Administration (FDA)" for a previous meta-analysis of suicidality.

But it's not clear whether the list of criteria was identical to that used by the FDA, or how that list was drawn up.

As such, it's hard to know whether the events they report on, such as agitation, nightmares and anxiety, can truly be seen as precursors to suicide or violence.

What were the basic results?

A total of 612 healthy volunteers took part in the 13 studies included in this analysis.

Researchers say they found 54 adverse events related to suicide or violence among 354 people who took antidepressants (15.25%) and 27 events among 258 people who took placebo drugs (10.46%).

This translates to an increased chance of having an adverse event of 85%, or almost double (odds ratio [OR] 1.85, 95% confidence interval [CI] 1.11 to 3.08).

The events reported in the studies were:

• agitation
• nightmares
• feeling jittery
• nervousness
• anxiety
• restlessness
• tremor (shaking)
• depression
• abnormal dreams
• abnormal thinking

There were no reports of people attempting suicide, thinking about suicide or acting in a violent way or threatening violence.

How did the researchers interpret the results?

The researchers say the types of events reported in the studies are recognised as "activation events" that can lead to suicide or violence.

They say they believe their summary under-reported the risk of adverse events, as they were unable to access full data from all trials.

"Antidepressants double the occurrence of events in adult healthy volunteers that can lead to suicide and violence," they conclude. "We consider it likely that antidepressants increase suicides at all ages." 

Conclusion

The harms and benefits of antidepressant drugs are hotly debated. While they can be helpful for some people, they can also cause side effects.

The difficulty is that some adverse events, such as increased thoughts about suicide or suicide attempts, are also symptoms of the conditions being treated, including depression and anxiety.

Most psychiatrists accept antidepressants raise the risk of suicide in children and adolescents with depression, so are only used with caution in this group.

This study is intended to untangle the symptoms of the conditions from the effect of the drugs by only looking at healthy volunteers who took part in drug safety trials, rather than people being treated for mental health conditions.

The meta-analysis found events like anxiety, agitation, nightmares and shakiness were more common among healthy adults taking antidepressants than those taking a placebo drug. There's no doubt that these feelings can be very distressing.

The crux of the argument about the study is whether these types of adverse events actually increase the risk of suicide and violence.

Even though these symptoms are included in categories of events that might lead to suicide and violence, the studies didn't report any cases where that actually happened.

If you've been prescribed antidepressants, you should be aware of the possibility of side effects.

If you're unhappy about the way they make you feel or you're not sure whether the benefits are greater than the harms, talk to your doctor.

It's very important not to stop taking antidepressants suddenly, as this can make your symptoms worse. Talk to your doctor about the safest way to reduce your dose over time if you want to stop taking them.

Other treatments for mental health problems like anxiety and depression include talking treatments, such as cognitive behavioural therapy. Many people find both medicines and talking treatments together work well for them.