Millions of depressed people. Most have been depressed before. If you have had 2 episodes, more than likely, you will have a third one. If you have had 3 episodes there's a 90 percent chance you will have a 4th. And so on. And so on. And so on.
The conventional wisdom is that depression is recurrent, and it often is, but we may have a misleading picture because our research samples have been biased towards those people who have been repeatedly depressed.If most episodes of depression are recurrences, most studies of depression, are, in effect, studies of recurrent depression.
According to a new analysis by Scott Monroe and Kate Harkness, there is a suprisingly large and special subgroup of the depressed who will never ever be depressed again. Of those with a first episode of depression, Monroe and Harkness estimate that about half will never have a return of depression in their lifetime. Never.
These are the people with a single lifetime episode of depression, or the SLEDs. Although carefully studying the SLEDs may teach us about how to escape the return of depression, we know very little about this group and the reasons why they have better outcomes.
The SLEDs have been ellusive. There are several reasons why SLEDs may not make it into research studies. SLEDs may less likely to conceive of themselves in terms of the depression diagnosis. It may have happened some time ago. Unless the episode were punishingly severe, it may have improved without the benefit of treatment. In fact, many SLEDs may prefer not to think about it, or in extreme cases even forgotten about the depression. So thoroughly have they moved on that it would require persistent questioning by an interviewer to uncover that there ever was a clinically significant depression episode.
In the dark world of depression epidemiology, the existence of the SLEDs is a ray of hope.
Do they rebuild their lives in special ways after depression? Do they learn more from their depression? Do they have different genes? Are they just plain lucky? Until we study them in large numbers, we can only speculate about what it is that makes the SLEDs special.
Monroe SM, Harkness KL. Recurrence in major depression: A conceptual analysis.Psychological Review, 118, 655-674.