The results throw into question the effectiveness of SSRIs (selective serotonin reuptake inhibitors), a family of antidepressants that includes Prozac. Since their introduction in 1987, the SSRIs have become the standard treatment for depression.
But the way the drugs are supposed to combat depression has always been controversial—some manufacturers have even admitted they don't know how they work—and critics have said any effect is purely placebo.
In their review of sertraline—the most commonly prescribed antidepressant—researchers at University College London agree. They monitored the effects of sertraline on 326 patients with depression and compared them against 329 similar patients who were instead given a placebo. After six weeks, the improvements in the sertraline group was just 5 per cent as measured on a depression score, a result so weak that it could be discounted.
"We were shocked and surprised. We definitely need better treatments for depression, and we need more research in this area," said lead researcher Glyn Lewis. It was one of the first studies to be independent and not funded by a drug manufacturer; previous studies paid for by a drug company have invariably produced positive results.
Sertraline's one benefit was in treating anxiety, achieving a 24 percent reduction in symptoms after six weeks.