Many have questioned the efficacy of the common antidepressant medications known as selective serotonin reuptake inhibitors (SSRIs).
They don't work for many people, studies have found, and even when they work they lose effectiveness quickly. Psychiatric medications have also been the common denominators in tragedies like mass shootings, which has increased concern about whether or not it is better to be depressed than homicidal.
The conclusion that these drugs are ineffective is partly based on a misinterpretation of the outcome of the clinical trials once conducted to demonstrate their efficacy, according to a study conducted by researchers at the Sahlgrenska Academy.
One reason for the questioning of the SSRIs has been that many of the clinical trials conducted years ago to prove their efficacy failed: critics have thus pointed out that less than half of the studies demonstrated a statistically significant difference between the tested SSRI and placebo. Clinical trials are required by law to be paid for and conducted by the company that would like to release a product, so researchers at the Sahlgrenska Academy analyzed data from all major company-sponsored placebo-controlled studies addressing the effect of any of three SSRIs – citalopram, sertraline and paroxetine – for major depression in adults.
“In order to measure the antidepressant effect, the pharmaceutical companies have unwisely assessed the reduction in the sum score for a large number of symptoms listed on a rating scale. However, the sensitivity of this instrument is markedly marred by the fact that many of these symptoms occur also in subjects without depression, while others are absent also in many depressed patients. For this and other reasons, the usefulness of this rating scale, which was constructed already during the 1950s, has since long been questioned," says pharmacologist Elias Eriksson. “We investigated what happens if one instead analyzes the effect of the treatment on the key item of the scale – depressed mood.”
• With the conventional measure of efficacy, only 44 percent of the 32 comparisons reveal a significant superiority of the SSRIs over placebo.
• When the Gothenburg researchers instead examined the efficacy on depressed mood, 29 of the 32 comparisons (91 percent) showed a significant difference favoring the active drug.
“Our conclusion is that the questioning of the antidepressant efficacy of SSRIs is to a large extent based on an unfortunate misinterpretation of the available data. The truth is that the scientific support for these drugs exerting an antidepressant impact is very robust across studies,” says Eriksson.