Why is this review important?
Major depression is a serious illness that can cause significant distress both to sufferers and their families. Major depression affects people's work, relationships and self-esteem. It also affects people physically, changing their sleep patterns, concentration and appetite. The symptoms of major depression can lead people to feel hopeless and even suicidal. Antidepressant medications are an effective treatment option for major depression, but many have unpleasant side-effects.
This review is important because it compares a new antidepressant, called agomelatine, with some other antidepressants used to treat major depression. Agomelatine works in a different way to existing antidepressants, it affects the hormone melatonin in the brain, and stimulates release of the brain chemicals dopamine and norepinephrine.
Who may be interested in this review?
People affected by major depression.
General Practitioners (GPs), psychiatrists and pharmacists.
Professionals working in adult mental health services.
Families and friends of people who suffer from major depression.
What questions does this review aim to answer?
Does agomelatine work better than other antidepressant medications?
Do patients tolerate agomelatine better than other antidepressants?
How do the side-effects of agomelatine compare with other antidepressants?
Which studies were included in the review?
In July 2013, we used electronic medical databases to find all published and unpublished medical trials that compared agomelatine with any other antidepressant. We also contacted Servier Laboratories (the developers of agomelatine) for additional information. To be included in the review, medical trials had to have a randomised design (i.e. be randomised controlled trials), and have adult participants (aged over 18) with a diagnosis of major depression.
We identified 13 medical trials, involving a total of 4495 participants, that could be included in the review. The reviewers rated the overall quality of the trials as 'moderate'. Almost all of the trials included were sponsored by the pharmaceutical company that developed agomelatine (Servier), which could introduce bias (research shows that funding strongly affects the outcomes of research studies).
What does the evidence from the review tell us?
The review included trials comparing agomelatine with a group of antidepressants called selective serotonin reuptake inhibitors (SSRIs), and one antidepressant from the serotonin–norepinephrine reuptake inhibitor group, called venlafaxine. Participants in the studies were followed up for between six to 12 weeks.
- Agomelatine was no more or less effective in reducing symptoms of depression than any of the other antidepressants.
- Agomelatine was no more or less effective in preventing relapse of depression than any of the other antidepressants.
- Agomelatine was tolerated better than venlafaxine (fewer people discontinued treatment), but the same as the SSRIs.
- Agomelatine caused a lower rate of dizziness than venlafaxine.
- Agomelatine caused a lower rate of vomiting, nausea and sexual side-effects than SSRIs.
What should happen next?
The reviewers conclude that agomelatine is not more effective than other antidepressants currently on the market. It did seem to be more tolerable to patients in terms of lower rates of some side-effects, however, the quality of trials was low and there were only a few trials that compared agomelatine with each medication. No firm conclusion on agomelatine can be made because of problems with reporting of data in the trials included. The authors recommend that further trials of agomelatine versus placebo (dummy pill), particularly in primary care settings (where the majority of patient/practitioner contact take place, e.g. GP surgeries), should be carried out to improve the quality of evidence.