Comparison of bipolar disorder type II and major depressive disorder

Compare patients diagnosed as DSM-5 type II bipolar disorder (BD2) vs. major depressive disorder (MDD).

We compared characteristics of 3246 closely and repeatedly evaluated, consenting, adult patient-subjects (n = 706 BD2, 2540 MDD) at a specialty clinic using bivariate methods and multivariable modeling.

Factors more associated with BD2 than MDD included: [a] descriptors (more familial psychiatric, mood and bipolar disorders and suicide; younger at onset, diagnosis and first-treatment; more education; more unemployment; fewer marriages and children; higher cyclothymic, hyperthymic and irritable temperament ratings, lower anxious); [b] morbidity (more hypomanic, mixed or panic first episodes; more co-occurring general medical diagnoses, more Cluster B personality disorder diagnoses and ADHD; more alcohol and drug abuse and smoking; shorter depressive episodes and interepisode periods; lower intake ratings of depression and anxiety, higher for hypomania; far more mood-switching with antidepressants; lower %-time depressed; DMI > MDI course-pattern in BD2; more suicide attempts and violent suicidal behavior); [c] item-scores with intake HDRS₂₁ higher for suicidality, paranoia, anhedonia, guilt, and circadian variation; lower somatic anxiety, depressed mood, insight, hypochondriasis, agitation, and insomnia; and [d] treatment (more lithium, mood-stabilizing anticonvulsants and antipsychotics, less antidepressants and benzodiazepines).

BD2 and MDD subjects differed greatly in many descriptive, psychopathological and treatment measures, notably including more familial risk, earlier onset, more frequent recurrences and greater suicidal risk with BD2. Such differences can contribute to improving differentiation of the disorders and planning for their treatment.