CME
Differentiating Bipolar Disorder
From Major Depressive Disorder:
A Case-Based Approach to Improving Diagnosis and Treatment in Primary Care
Michael J. Gitlin, MD
UCLA Semel Institute
for Neuroscience and Human Behavior
Los Angeles, California
The Course Director, Dr. Michael J. Gitlin, provides his answers below.
There are no areas of greater controversy than the optimal treatment for bipolar depression. The core problems are: 1) the very weak database demonstrating efficacy of antidepressants in treating bipolar depression; 2) the concerns about the potential of antidepressants to cause hypomanic/manic switches when prescribed for bipolar depression; 3) the lack of consistent efficacy for many of the mood stabilizers in treating bipolar depression; and 4) the disparity between the data and a great deal of clinical experience in this area. The best data for bipolar depression are in support of quetiapine and the olanzapine/fluoxetine combination. However, side effect considerations make these two options somewhat problematic. There are more inconsistent data in support of lamotrigine; however, that agent is used clinically with great regularity. Despite the lack of consistently positive data, the combination of antidepressants plus mood stabilizers is still commonly prescribed by expert clinicians for bipolar depression.
From all the information that we have about bipolar disorder, it is a lifetime disorder. Patients do not “grow out” of bipolar disorder because it is not a developmental phase, but a recurrent disorder. In general, for patients who have exhibited recurrent mood episodes of bipolar disorder, discontinuing effective maintenance treatment is very likely to result in a recurrence of the disorder. As an example, in a study of bipolar patients discontinuing lithium while euthymic, recurrence rates were 75% over 5 years; recurrence rates were somewhat higher in bipolar I compared to bipolar II patients [Faedda GL et al. Arch Gen Psych. 1993;50:448-455]. Therefore, if this young adult patient has true bipolar disorder, discontinuing mood stabilizers would be a risky decision.
From the question, it is unclear if the patient is presenting with an acute manic/hypomanic episode or with a history of bipolar disorder but is currently euthymic. If the patient is acutely manic/hypomanic and if we exclude cost considerations, most patients in such a circumstance would be treated with a second-generation antipsychotic such as olanzapine, quetiapine, or aripiprazole. However, these are all rather expensive. Cheaper alternatives would be either risperidone (which is now generic but still somewhat costly), a first-generation antipsychotic such as perphenazine, haloperidol or thiothixene, or lithium. The only problem with lithium is that the treating family practitioner would need to be familiar with lithium doses, the use of serum lithium levels, etc. If the need was for a maintenance treatment, without doubt, lithium is the least expensive option available (with the same caveat about the requirement for some knowledge of how to dose and monitor the drug).
The diagnosis of bipolar (BP) II disorder is fraught with difficulties. Since, by definition, the racy episodes of BP II patients are milder than full-blown manias (as is seen in BP I disorder), it is easy for patients, family members, and clinicians to miss these episodes. According to the DSM-IV, the hallmark of a hypomanic state is an alteration in mood—either euphoric/expansive or irritable/paranoid. However, irritability is a very nonspecific sign in psychiatry, seen in a variety of diagnoses. Euphoric, grandiose, expansive mood and thinking is somewhat more specific for bipolar disorder. The other situations/disorders in which these symptoms can be seen are stimulant use and abuse, and, transiently, in Cluster B personality disorders, such as narcissistic or borderline individuals. However, the single most important distinguishing diagnostic point in making an accurate diagnosis of BP II disorder and ruling out a similar-appearing disorder is the course of the symptoms. Bipolar disorder is an episodic disorder, with episodes of both mania/hypomania, depression, and asymptomatic periods. Chronic hypomania is rare indeed. So, if patients present with symptoms suggestive of hypomania, but the symptoms have been present unremittingly for years at a time, it is less likely to be BP II disorder. On the other hand, episodic or cyclical symptomatic times should be considered more highly for the diagnosis of bipolar disorder.