Should DSM-V include a diagnostic category for people with major depressive disorder with subthreshold hypomania? This isthe question that is at the center of the paper I just read. My initial answer to this question was a resounding “No”,because of some of the challenges the authors discuss. However, having read the paper, I have come to the conclusion that there may be some use for subsyndromal hypomania as a separae diagnosis.
The authors start by evaluating the prevalence and possible misdiagnosis of unipolar depression vs. bipolar disorder. Previous research found that aproximately 40-50% of people with major depressive disorder have a lifetime history ofsubsyndromal hypomania, depending on the precise criteria used. Furthermore, individuals with such a history are much more likely than individuals without subthreshold hypomania to eventually be diagnosed with bipolar disorder, usually even bipolar I.
In addition, those with major depression and a history of sunthreshold hypomania generally have a worse outcome, more mood episodes, and more work impairment than depressed individuals without a history of subsyndromal hypomania. With regards to family history, people with major depression and subthreshold hypomania are more likely to have family members with mania or other bipolar disorders than those with only depressive symptoms. An early onset (before age 21) of depression and a presentation with atypical features are also characteristic of people with subthreshold hypomania.
For the above reasons, the authors recommend that subthreshold hypomania be included in DSM-V. There is some debate as to which criteria should be used, but they advise an emphasis on overactivy rather than just mood elevation and a duration of at least two days with at least three of seven hypomania symptoms met. The authors also recommend that subthreshold hypomania should be seen as in the middle between pure depression and bipolar II. They argue against the diagnosis of individuals with major depression and subthreshold hypomania as bipolar, because of the stigma this can create.
This stigma was one of my initial reasons to oppose the widening of the bipolar spectrum to include subsyndromalhypomania. The other reason, which the authors also address, is the potential overprescription of antipsychotics and moodstabilizers. There is no evidence that antidepressants would be bad for individuals with major depression who might havesubthreshold hypomania, and neither is there evidence that mood stabilizers or antipsychotics prevent a worsening fromsubsyndromal hypomania to full-blown (hypo)mania. Given the fact that antipsychotics and mood stabilizers have significantside effects, it is not recommended that they be used without merit.
However, the authros do argue for better psychosocial treatmetn of individuals with depression and subthresholdhypomania. They state that cognitive-behavioral therapy, psychoeducation and some other psychosocial interventions may betailored more effectively towards those with subthreshold hypomania if this is idenftified in people with major depression.This is also in light of the worse outcome usually seen in individuals wiht subtreshold hypomania. Psychotherapy,apparrently, might help people manage their hypomanic symptoms.
So, contrary to what I expected, the authors of this study are not Big Pharma puppets who advocate the widespread use ofthe newest and most expensive medications. They also, interestingly, do not seem to suggest that mood disorders as a wholeare underdiagnosed, or that in general more people should be seen as mentally ill. They rather try to pinpoint the symptomsof a subgroup of depressed individuals more precisely than could previously be done. This does not directly change myopinion on subthreshold bipolar yet, but it does give me some thought.
Reference
Nusslock R, Frank E (2011), Subthreshold Bipolarity: Diagnostic Issues and Challenges. Bipolar Disorders, 13:587-603. DOI: 10.1111/j.1399-5618.2011.00957.x.
