Rapid Antidepressants? Perception Changes Fast; Mood, Not So Much

Do antidepressants actually start to work immediately?  Although people with depression don't usually feel better right away, a fascinating new study suggests that these medications change the way people see the world within hours, not the two to six weeks that patients typically must wait before they sense that their mood has lifted.  The research could help explain why cognitive behavioral therapies and medication work better together.

Depressed people's perceptions of themselves and the world have a measurable negative skew. But the study—which used an antidepressant that has not been approved in the U.S. called reboxetine—found that depressed people given the drug were much more likely to recognize happy faces.  They also performed better at a task that involved identifying and recalling positive qualities that they'd been asked to consider as potentially applying to themselves.

Three hours after taking the drug, says lead researcher Catherine Harmer, PhD, head of the Psychopharmacology and Emotion Research Lab at Oxford University in England, “The depressed patients' performance was similar to the healthy controls under normal conditions.”

However, they reported no improvement in their mood or anxiety level, consistent with the traditional view that these drugs don't “kick in” immediately.

Explains Harmer, “Usually it takes some time before a change in emotional processing changes the way we actually feel.  This is because a change in emotional processing affect how we filter information we are presented with - so we need enough experience of the world, other people, memories etc.-- before a change in how we are filtering them affects how we feel.”

Since depressed people have been missing positive signals from others and from themselves since they became ill, they probably need repeated experience of getting these signals again before their mood lifts.

Harmer says, “As a simple example, imagine you are depressed, but after taking an antidepressant you start to see that your friends are smiling at you. This might make you feel more liked, more accepted or more likely to meet up with them or other friends again.  However, on its own, it won't be enough to lift deeply ingrained depression.  Over weeks or even months as you start to see things differently, this will affect how you behave and how you feel.”

Cognitive behavioral therapy—which is the talk therapy with the most research support as a treatment for depression—directly challenges people's negative thoughts and perceptions, so it's easy to see how drugs might augment it.

Says Harmer, “This work suggests that antidepressant drug treatment could work in a similar way to cognitive theories of depression.  We need further research to understand how they truly interact and whether it is possible to potentiate the mechanisms underlying either treatment by using them in combination.”

The research was published in the American Journal of Psychiatry and the researchers disclose past pharmaceutical industry funding.