In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is double depression. This post uses a lot of abbreviations, which are summarized down at the bottom of this post.
The term double depression is sometimes used to describe the state when two types of depression (major depressive disorder and dysthymia) occur at the same time. The term has been in use since 1982, but it’s not a diagnostic term in the DSM-5.
Major depressive disorder (MDD) is what most people think of when it comes to depression. It involves at least one episode that fulfills the criteria for a major depressive episode (MDE). That basic building block on an MDE can also be found in bipolar disorder and schizoaffective disorder).
Earlier DSM versions
In the DSM-III, and again in the DSM-IV, dysthymic disorder (aka dysthymia) was a distinct diagnosis from MDD. It applied when someone had depressive symptoms that didn’t meet the criteria for an MDE (in number or severity), but were pervasive and present pretty much all of the time for at least two years. Basically, it was a milder form of depression that stuck to you like glue.
Sometimes, dysthymic symptoms may worsen to the extent that they meet the criteria for an MDE, which might then be described as a double depression.
Then along came the DSM-5. It created a new diagnosis, persistent depressive disorder (PDD). This encompassed both the former diagnosis of dysthymia and people with full MDD who met that 2-year stuck to you like glue criterion. Double depression would fall under that hodgepodge somewhere.
In a rather odd quirk of the DSM-5, I now technically have an additional diagnosis of PDD because my treatment-resistant MDD has persisted without a break for more than two years.
Is double depression a useful construct?
A recent meta-analysis that looked at results from previous studies showed that people with double depression don’t tend to respond to medications as those with MDD or PDD alone. I’m not sure if that’s actually indicative of a distinct population or if people fell into that double depression category because they were harder to treat in the first place.
Why the confusion? The DSM is a pretty blunt instrument. It organizes things in a broader sense pretty well, but when it comes to fine distinctions, it’s not so good. Depression is a thing, absolutely. There are different characteristic patterns of depression, absolutely. But are those patterns shades of the same thing, or do they represent distinct phenomena? Who knows.
Then there’s what feels right. To me, it feels like it misses the boat a bit that I happen to fall into an additional category by default. Especially when one of my key symptoms is only on the MDE criteria list, not the dysthymia list. It’s not like, say, a schizophreniform disorder diagnosis, which is by definition basically a placeholder until you meet the length of time for a diagnosis of schizophrenia. That’s a switch of diagnosis; this is an addition of diagnosis. I don’t actually care; my dimwit of a doctor certainly has no idea that I technically have this extra diagnosis now, and it changes nothing in my life.
What do you think of the concept of double depression? Is it something you’ve experienced?
- DSM: Diagnostic and Statistical Manual of Mental Disorders
- MDD: major depressive disorder
- MDE: major depressive episode
- PDD: persistent depressive disorder, formerly dysthymia
You can find the rest of the what is… series in the Psychology Corner.