The history of bipolar disorder is a long one. It goes back to at least the first century AD when Aretaeus of Cappadocia described the behavior of patients with quips such as “simple, extravagant, munificent, not from any virtue of the soul, but from the changeableness of the disease,” and “unreasonably torpid, without any manifest cause: such is the commencement of melancholy.” Sound familiar? Maybe a little verbose, but overall it seems pretty accurate. From there, knowledge of the disease progressed fairly slowly until the 20th century. Carl Jung started describing another feature of the disease in 1904, which gave rise to the hypomanic characteristic. Then, manic-depressive disorder research began chugging like a steam engine.
In the 1980’s, the writers of the Diagnostic and Statistical Manual of Mental Disorders (DSM) began distinguishing different forms of bipolar disorder based on specific sets of symptoms. Finally, in 1994, bipolar disorder type II was added to the DSM IV. Now a patient who had not been previously diagnosed with bipolar disorder due to the lack of manic symptoms could be given the diagnosis for hypomania, the same thing Jung described 90 years earlier.
Initially, the bipolar II diagnosis was created to differentiate those who suffered from unipolar depression (major depressive disorder) with additional bipolar-type symptoms but had not experienced a full manic episode. A manic episode requires an elevated or agitated mood with increased activity and energy levels that lasts at least one week. For hypomania, with updates in the new DSM V, it only takes two days of an increase in energy or activity (elevated or irritable mood was removed for the new DSM). It can be a thin line and and, honestly, pretty subjective, especially when you consider that only one manic episode changes the diagnosis.
So why, then, is bipolar II considered a “lighter” form of bipolar disorder? In a nutshell, bipolar I is more in-your-face. Patients tend to have more severe symptoms and those symptoms interfere more with everyday functioning. Hospitalization is more common with bipolar I. Also, psychosis is rarely experienced in bipolar II, while 70% of bipolar I patients will experience it at some point.
So, in that sense, bipolar II is milder than bipolar I, but that’s not the whole story.
While bipolar I may have more severe symptoms, bipolar II has its own characteristics. First, bipolar II patients tend to experience higher rates of rapid cycling. With rapid cycling, patients have at least four cycles per year and can end up having multiple cycles per day in the most severe cases. This characteristic can be more closely related to borderline personality disorder than bipolar I. The link between bipolar II and borderline personality disorder also exists due to the prevalence of atypical depression in bipolar II rather than bipolar I disorder.
Second, depressive cycles, whether typical or atypical, are often longer with bipolar II patients than bipolar I. So, their treatment may need to be more focused on keeping depression under control whereas a bipolar I patient may struggle more with the manic side. Bipolar II patients are often less self-aware about their condition, and they may end up not seeking the treatment they may need.
Even more difficulties can arise when diagnosing bipolar II disorder. Because it’s considered a “soft” version lying between unipolar depression and bipolar I, it’s often misdiagnosed in any number of ways. If hypomania is missed and is diagnosed as unipolar depression, then a patient is likely to be prescribed antidepressants, which can actually worsen bipolar disorder. Contrarily, if a patient is given mood stabilizers for bipolar disorder, it may not be the optimal treatment for major depressive disorder. With the loosening of the diagnostic criteria in the DSM V, this could grow into a larger problem.
What this all boils down to is that it’s not “us” versus “them.” There’s no need to compare bipolar I and bipolar II to see which is “worse.” They’re different and they’re both awful. Even within each diagnosis, the severity varies between patients. We need to focus on getting better and just be supportive all around.