At CONvergence two weeks ago, I and a few other people did a panel on myths about mental illness. It was really great, and I hope that there will be a video of it up eventually. At one point, I tangentially mentioned atypical depression, a type of depression that is sometimes contrasted with melancholic depression, or the “typical” kind.
Atypical depression is the type that I have, and that might be part of the reason it took me something like seven years to realize that I had depression at all. A few people have since told me that they didn’t even realize atypical depression was a thing. So I decided to write a brief overview of it in the hopes that more people who don’t have a name for what they’re going through might find a name for it.
There are some “classic” depression symptoms that most people think of when they think of depression: being numb or sad most of the time, being unable to take joy in things you used to like, insomnia, and loss of appetite and weight. You think of the person lying in bed unable to care about or take pleasure in anything.
Atypical depression has a rather different set of features. Instead of insomnia, you may have hypersomnia (oversleeping). People with atypical depression might regularly need to sleep 10 or 12 or even more hours. Instead of loss of appetite, you may overeat and/or gain weight. Instead of being numb or just uniformly sad, you have high mood reactivity, or mood swings. You may find that you’re able to enjoy things and feel happy when things are going very well, but as soon as things are neutral or even just a little bit bad, you feel horrible again. There are two other symptoms that are sometimes present: leaden paralysis, or the feeling that your limbs are very heavy and difficult to move, and high rejection sensitivity, which means being overly concerned about people not liking you or rejecting you, to the point that it impairs your social functioning.
Unsurprisingly, these different sets of symptoms mean that different types of antidepressants may work best for each type. I will quote Wikipedia here, since it’s sourced and there’s no good reason to rephrase it:
Medication response differs between chronic atypical depression and acute melancholic depression. Some studies suggest that the older class of antidepressants, monoamine oxidase inhibitors (MAOIs), may be more effective at treating atypical depression. While the more modern SSRIs and SNRIs are usually quite effective in this illness, the tricyclic antidepressants typically are not. The wakefulness-promoting agent Modafinil has shown considerable effect in combating atypical depression, maintaining this effect even after discontinuation of treatment. 
I don’t know how useful this information is to you if you think you may have atypical depression, but at least now you know that if your symptoms fit this pattern but your psychiatrist prescribes you a tricyclic antidepressant without further explanation, it might be worth bringing up this research. In addition, if SSRIs haven’t been working for you, you might ask your psychiatrist about trying MAOIs rather than a different SSRI or a higher dose of the same one.
In terms of therapy, I can’t seem to find any studies on the effectiveness of different types of therapy on the different types of depression (that may be because Google Scholar is actually a terrible search engine), but my educated guess would be that dialectical behavior therapy (DBT) would be extra helpful for atypical depression as opposed to melancholic depression. DBT is a type of therapy developed specifically to treat borderline personality disorder, which involves lots of mood swings, rejection sensitivity, and general troubles with managing emotions. DBT contains a lot of the same techniques as cognitive-behavioral therapy (CBT; the standard of evidence-based treatment), but it also emphasizes mindfulness and learning to cope with strong emotions. Atypical depression, with its mood swings and interpersonal issues, might be especially amenable to it.
To the extent that psychodynamic therapy is effective (actually, plenty of studies suggest that it might be), it might also be more effective on atypical depression than other approaches. Atypical depression tends to have an earlier onset, and people may experience it as an aspect of their personality that is rooted deeply in their life experiences. When practiced well, psychodynamic therapy may be useful for resolving these issues. But none of this is to say that standard CBT should not be tried.
During my senior year of college, I asked a professor who studies the neuropsychology of mood disorders whether or not he knew of any research on neurological differences between atypical and melancholic depression. After all, there’s been plenty of research on how depression affects the brain–in terms of active brain regions, neurogenesis (growth of new neurons) in various regions, and so on. Were all these studies really done using patients who might’ve had what looks like two nearly-completely different illnesses? Apparently. My professor wasn’t aware of any such studies, and I’ve only found one myself: some research that examined which hemisphere of the brain responds more to a particular face test, and in atypical depression patients, the right hemisphere was much more active than it was in melancholic depression patients and in non-depressed controls. The authors write, “This is further evidence that atypical depression is a biologically distinct subtype and underscores the importance of this diagnostic distinction for neurophysiologic studies.”
There also seems to be some evidence that atypical depression in particular is linked to thyroid dysfunction, which may explain some of the physical symptoms. However, the results seem to be rather complicated and confusing, and it’s definitely not a simple causative link.
Although the diagnostic criteria for depression contain both sets of symptom patterns and there’s even a special indicator for “atypical features,” the popular conception of depression is of the melancholic type, not the atypical type. This means that many people, believing that depression necessarily means “being completely miserable all of the time always,” may not realize that they might have depression and can benefit from treatment.
Atypical depression presents a classic boiling-frog problem. Because you are in fact capable of feeling happy for short or medium stretches of time, it can take a serious increase in symptom severity to realize that there’s anything wrong. Incidentally, as I mentioned, atypical depression also tends to have an earlier onset than melancholic depression, which means that you may spend your entire post-childhood life that way. For some people, certainly for me, it felt like it was “just my personality.” To make things even more confusing, the rejection sensitivity tends to be present even during periods of time when the rest of the symptoms are in remission. But when it comes to mental health, nothing is ever really “just your personality” if you don’t want it to be.
Hopefully, this overview will help people–at least the people who read this blog–broaden their awareness of what depression is. If there’s anything I missed in terms of research, by the way, please let me know. As I mentioned, my Google Scholar-fu is much worse than my Google-fu.