Why Early Diagnosis of Bipolar Disorder Can Be Difficult

In an article recently published in Lancet Psychiatry, Sameer Jauhar and colleagues review the clinical presentation, natural history, and treatments for first-episode bipolar disorder—specifically, first-episode mania. They conclude that, as is true for most psychiatric disorders, early intervention is important. Treatments include medications, psychological therapies, and interventions involving family members and vocational recovery. In addition, these authors stress the importance of treating comorbid drug or alcohol use disorders. They note that there is a paucity of outcome research regarding acute and maintenance treatments for first-episode bipolar disorder and that more research is necessary to upgrade current treatment guidelines.

In an appendix, Jauhar and colleagues include an essay by a patient detailing his years-long experience in obtaining a diagnosis of bipolar disorder. In an accompanying editorial, Gin Malhi highlights this patient narrative and discusses the inherent difficulties in making an initial diagnosis of bipolar disorder. These difficulties are evident to academic psychiatrists who teach psychiatric residents and medical students. After evaluating patients with a prior diagnosis of bipolar disorder, it is common to conclude that many of these patients do not have bipolar disorder. The reasons for such diagnostic inaccuracies are succinctly summarized in Malhi’s provocative and useful commentary.

As Malhi points out, an episode of mania is necessary to make a definitive diagnosis of bipolar disorder. One reason for inaccurate diagnosis is that street drugs can produce manic-like symptoms. For example, stimulant intoxication often leads to manic-like behaviors. Determining whether substance use is the primary etiology of manic symptoms can be difficult since individuals with true bipolar disorder are prone to use street drugs.

Careful gathering of a comprehensive longitudinal history coupled with observation of the person when drug-free is often required in order to accurately determine if the person has bipolar illness. This determination is important because treatments for bipolar disorder with coexisting substance use disorder differ from treatments for substance use disorder unaccompanied by bipolar disorder.

Another confounding variable making the diagnosis of bipolar disorder difficult is that borderline personality disorder can present with symptoms that overlap with manic symptoms. By interacting with a patient on an inpatient unit and gathering further history, it is not unusual to conclude that a patient who had been diagnosed with bipolar disorder actually has symptoms consistent with borderline personality disorder. The affective instability, erratic, and impulsive behaviors that occur in this disorder can easily be mistaken for symptoms of bipolar disorder, particularly in the presence of substance use. The treatments for bipolar disorder and borderline personality disorder are quite different, and it is important to differentiate these two disorders.

The symptoms of a first manic episode can vary and, at times, psychotic symptoms may dominate. It may be difficult to determine if such symptoms are due to bipolar disorder, schizophrenia, or schizoaffective disorder. Distinguishing among these disorders often requires longer-term follow-up. Recent evidence suggests that bipolar disorder and schizophrenia may share some biological underpinnings.

Another difficulty in making a diagnosis of bipolar disorder is that individual symptoms that define manic episodes can occur in individuals without the disorder. For instance, people may speak rapidly on occasion and be hard to interrupt. Occasional irritability and moodiness is common. Increased interest in sexual activity is not unusual, especially in teenagers. Bouts of high energy and decreased sleep are not uncommon, especially when someone is working on an interesting project or facing a deadline. As Malhi notes, even occasional psychotic symptoms can occur in healthy individuals. A manic episode only becomes clearly defined when many of these behaviors occur together and persist for an extended period of time.

One other consideration in making the initial diagnosis of bipolar disorder difficult is that the first presentation of bipolar disorder is often an episode of depression. Symptoms of depressive episodes that predate a manic episode cannot be distinguished from depressive episodes associated with unipolar depression, i.e., depression without an eventual manic episode, or depressive episodes that arise in the context of other psychiatric illnesses. Unipolar depressive episodes are much more common than bipolar depressive episodes, and it is clinically difficult, if not impossible, to determine if a particular depressive episode is the beginning of bipolar illness.

Eventually, there may be biomarkers based on blood tests or functional imaging tests that will assist in diagnosing bipolar disorder or in determining whether a depressive episode is likely the first episode of bipolar disorder. Unfortunately, such biomarkers do not currently exist.

The editorial by Malhi is an excellent complement to the review article by Jauhar and colleagues. Both articles remind us that we have a lot to learn about bipolar disorder—an illness that often responds to appropriate treatment, occurs in about 1 percent of the population, and is associated with substantial disabilities and increased mortality.

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This article was written by Eugene Rubin, M.D., Ph.D. and Charles Zorumski, M.D.