Can Atypical Major Depression Signify Bipolar Disorder?

You're probably wondering why the smiling woman is in a series on the major depressive disorder (MDD)? Well, in contrast to most depressive episodes, someone with atypical MDD can experience positive mood reactions, amongst other depressive anomalies. However, despite the presence of positive mood reactions, atypical features should not be thought of as a pleasant experience.

Does Atypical Mean Rare?

The term atypical features does not indicate it is uncommon. It is noted in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), that:

Atypical depression has historical significance (i.e., atypical in contradistinction to the more classical agitated, endogenous presentations of depression that were the norm when depression was rarely diagnosed in outpatients and almost never in adolescents or younger adults.)

In essence, it is melancholia's nemesis. The patient can have periods of feeling better in response to positive experiences, unlike the unrelenting torment of melancholia. It is also atypical in that most people who get depressed have insomnia and appetite loss; here, it's just the opposite.

Like melancholic features, very current prevalence rates are hard to come by. There is minimal recent data on prevalence, but the atypical features experience is believed to account for up to 36% of MDD cases (Łojko & Rybakowski, 2017). It also seems to first appear in the teens and early 20s, earlier than other MDD forms; be more chronic and more prevalent in women, and be the kind of depression most associated with bipolar disorder (Singh & Williams, 2006; Barlow & Durand, 2015, Buzuk et al., 2016). This, of course, does not mean that everyone with atypical features will develop bipolar disorder, however.

The Presentation

Atypical features present an interesting MDD subtype. Aside from the ability to experience some level of a good mood, we also encounter the unusual symptom of leaden paralysis, like Barbara:

Barbara, a working mother of two and devoted wife, was no stranger to depression. She adored her family and enjoyed her part-time work at the library. Barbara knew a depressive episode was coming on when she began feeling drained at the thought of having to work or care for the kids after daycare until her husband, Jack got home.

It never failed that her down-in-the-dumps feeling led to eating a lot of comfort foods. She'd berate herself as she ate a second bacon and egg sandwich many mornings, but she was simply feeling like eating more. At dinner, Barbara plowed through extra helpings of dinner and desserts.

Within a week, Barbara was frowning in the mirror, checking if the weight gain she was starting to feel was observable. Soon, she was not only bedraggled by tiredness but could go for hours feeling as if she wore weighted clothing. It was impossible to drive to the library and work for four hours each day or chase the kids around.

Thankfully, Jack had an understanding boss, and he could work from home on those days. Despite her feeling down, Barbara would maintain a level of brightness when Jack was home during these periods.

The official criteria for atypical features, according to the DSM-5, are as follows:

• Mood reactivity must be present. Coupled with at least two of the following:
• Excessive appetite/weight gain
• Excessive sleep
• Leaden paralysis is especially felt in the extremities.
• A sense of interpersonal rejection that is present even when the person is not in a depressive episode

Treatment Implications

As with melancholic features and anxious distress, atypical features have special considerations for therapists and evaluators.

1. Given atypical features are highly associated with bipolar disorder, we should be vigilant for any manic/hypomanic symptoms as we get to know the patient. As you're probably aware, bipolar disorders are highly correlated with genetics and require pharmacological intervention to stabilize well, and the sooner the intervention, the better. Episodes can be prone to kindling effects, meaning that the more episodes someone has, the more prolonged and more severe subsequent episodes may become.
2. Atypical depression, as noted, tends to be more chronic and severe in episodes, which raises suicide risk. Also, as noted in Durand & Barlow (2015), people with atypical features seem more apt to have co-occurring anxiety disorders, compounding their misery. Imagine feeling weighted down to the point it is hard to move, as weight piles on from overeating, further sinking your self-esteem. Add to this feeling no good to the point you believe the world is rejecting you, coupled with a co-occurring anxiety condition! Assessing for risk of suicide is very important in the presence of atypical features.
   
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3. As with the other MDD subtypes thus far, referral to psychiatry is exceptionally important here. This is because of the significant hypersomnia, over-eating, and psychomotor abnormalities, symptoms that often respond well to medication. Getting a patient to have the energy to attend therapy is a big step. Curbing the appetite will help with self-esteem issues and managing the sugar spikes and crashes many seem to experience from indulging in comfort foods, which surely doesn't help the moodiness.

You may have heard of monoamine oxidase inhibitors (MAOIs), the earliest antidepressants. Interestingly, these were discovered as antidepressants used in tuberculosis wards during the middle of the last century (Mendelson, 2020). These are not used much nowadays except as a last resort because they don't interact well with other medications and can cause serious complications if certain foods are eaten (Culpepper, 2013). Other more modern antidepressants, sometimes in combination, are often prescribed to help quickly curbing appetite and increasing energy.

Working with patients with atypical features again presents a significant challenge to therapists. However, their ability to experience windows of a more positive demeanor despite the depression can also make therapy less of a chore. Ultimately, atypically-depressed patients can meet with success while working closely with a therapist and psychiatrist, who are also keeping vigilant for suicide and emerging bipolar disorders.