LONDON (AP) _ Most patients treated for depression should remain on medication after their gloom has lifted, new research suggests.
Over the last decade, scientists have discovered that depression, which plagues millions, recurs repeatedly in four out of five patients. However, it is still mostly tackled as an episode, and drugs are usually prescribed for no more than two or three months.
A comprehensive review of 30 years of evidence, published this week in the Lancet medical journal, suggests that is the wrong approach. In the analysis, those who stayed on antidepressants were half as likely to have another bout of depression as those who stopped taking medication.
``Everybody thinks that when their symptoms are under control they can withdraw the treatment,'' said one researcher, Dr. David Kupfer. ``It looks like the people who need medication to get better, need it to stay better.''
The World Health Organization has identified depression as the disease with the fourth heaviest burden to society and predicts that it will become the second leading cause of disability worldwide by 2020 _ after heart disease _ unless strides are made in prevention, diagnosis and treatment.
More than 340 million people worldwide, 18 million in the United States alone, are estimated to have depression at any one time. Experts calculate that 13 percent of men and 21 percent of women get severe depression sometime during their lives.
The Lancet researchers combined the information from 31 studies conducted over the last 30 years on patients with recurrent bouts of depression. The patients had done well on short-term antidepressant therapy and then were randomly assigned either continued drug treatment or fake pills.
The studies involved a total of 4,410 patients. Most of the studies followed patients for a year, but some tracked them for three years. The studies examined a wide range of antidepressants.
Only 18 percent of those who stayed on their drugs relapsed during the study period, compared with 41 percent of those who discontinued their medication.
It did not seem to matter which antidepressant was used.
``This calls for a clear recognition that you need to think about this as a chronic recurrent disease, and it's the same way you would treat hypertension, diabetes or chronic asthma,'' said Kupfer, chair of psychiatry at the University of Pittsburgh Medical Center.
Although experts differ on whether depression turns recurrent after two episodes or three, they agree that long-term treatment is not necessarily appropriate after a single bout of depression.
``It doesn't apply to someone who's had some kind of crisis and has got depressed for the first time and it's all rather understandable,'' said Dr. Guy Goodwin, a professor of psychiatry at Oxford University in England, which led the Lancet analysis.
And not all depression requires drugs.
Mild to moderate depression can be treated by psychotherapy, experts say, but when the condition is severe _ such as when there are suicidal thoughts _ medication is needed.
About 70 percent of people with depression are treated by family doctors, who prescribe the vast majority of antidepressants.
``Nobody pays any attention to the family history, the genetics, the clinical features, the fact that this is the third episode. They don't treat this as a chronic disorder, they treat it as a situational disorder and that's because we spent several decades teaching that,'' said Dr. John Greden, a depression expert who was not connected with the research.
Greden _ chair of psychiatry and director of the Depression Center at the University of Michigan in Ann Arbor _ said primary care doctors are getting better at diagnosing and treating depression.
``But in most cases, primary care doctors don't know enough about it, are uncomfortable with it, don't have much time with each patient and don't know what to do when the patients complain of side effects,'' he said. ``So they tend to respond by going to lower doses, which don't work.''
So far, there is no reason to believe there are any long-term health risks to continued antidepressant therapy, scientists say.
But there is evidence that recurrent depression could be bad for the brain.
``When people get ill and stay depressed, you can actually measure changes on MRI scans of the brain. You can actually see shrinkage in certain areas,'' Goodwin said. ``People's memories are chronically impaired, and recovery seems to become very difficult when severe depression has lasted for a long time. We don't really know which is the chicken and which is the egg there, but the association is very clear.''