The Mood Disorder Questionnaire: A Simple, Patient-Rated Screening Instrument for Bipolar Disorder

Abstract

Bipolar disorder is frequently encountered in primary care settings, often in the form of poor response to treatment for depression. Although lifetime prevalence of bipolar I disorder is 1%, the prevalence of bipolar spectrum disorders (e.g., bipolar I, bipolar II, and cyclothymia) is much higher, especially among patients with depression. The consequences of misdiagnosis can be devastating. One way to improve recognition of bipolar spectrum disorders is to screen for them. The Mood Disorder Questionnaire is a brief, self-report screening instrument that can be used to identify patients most likely to have bipolar disorder. Once identified, and subsequently appropriately diagnosed, the lives of those with bipolar disorder may be considerably improved.

Primary care providers in the United States treat many patients with depression. Although 60% to 70% of patients with depression improve, about one third do not, and many do not achieve full remission.¹ One reason for poor or incomplete response may be undiagnosed bipolar spectrum disorder. Bipolar spectrum disorders have been defined in a variety of ways^2,3 but typically include bipolar I, bipolar II, cyclothymia, and bipolar disorder not otherwise specified. Signs and symptoms are diverse and include impulsive behavior, alcohol/substance abuse, fluctuations in energy level, and legal problems (Table 1). In addition, the depressed mood typically associated with the depressive phase of these disorders is often misdiagnosed as depression. Consequently, bipolar disorder may go unrecognized for 7 to 10 years.^4,5 Furthermore, many patients with bipolar disorder undergo 3 or more professional evaluations before receiving correct diagnosis and treatment.⁴ The consequences of a delayed or incorrect diagnosis can be devastating, as the medical management of bipolar disorder differs substantially from that of depression. This article provides an overview for screening and diagnosis of bipolar disorder in the primary care setting.

Table 1.

Signs and Symptoms of Bipolar Disorder

FINANCIAL AND SOCIAL COSTS OF BIPOLAR DISORDER

According to 1991 data compiled by Wyatt and Henter,⁶ direct costs for inpatient and outpatient care associated with bipolar disorder are thought to total $7 billion. Indirect costs account for approximately $38 billion in expenditures.⁶ A more recent analysis reported by Begley and colleagues⁷ in 2001 suggests lifetime cost of patients diagnosed with bipolar disorder in 1998 will be $24 billion, with average lifetime cost per patient ranging from about $11,000 for persons with a single manic episode to over $600,000 for those with chronic or nonresponsive disease. Indeed, bipolar disorder is sixth among all health conditions in terms of causing disability across the world.⁸ Greater recognition of bipolar disorder warning signs in the primary care environment could very likely improve treatment outcomes, which could translate to a reduction in use of expensive treatment facilities.

Untreated/Misdiagnosed Bipolar Disorder

Results from the National Depressive and Manic-Depressive Association (NDMDA) survey⁴ indicate that 73% of patients with bipolar disorder were misdiagnosed on initial presentation to a health care professional. The most frequent misdiagnosis was depression. Other misdiagnoses included anxiety disorder, schizophrenia, personality disorder, and alcohol abuse.⁴

Several doctor's office clinical studies confirm these survey findings. For example, in 1 family practice setting, over one quarter of patients presenting with depression or anxiety suffered from bipolar spectrum disorder.⁹ Similarly, in a sample of 261 outpatients with bipolar disorder, Suppes and colleagues¹⁰ reported an average 10-year elapse between the first symptoms of bipolar disorder and first treatment. During this period, many patients received antidepressants without concurrent mood stabilizers. The situation is not improving. The NDMDA survey was repeated in 2000. Unfortunately, over one third of the new sample of bipolar patients waited at least 10 years for a correct diagnosis, just as in 1994.¹

One reason for this substantial delay in diagnosis and appropriate treatment is that bipolar patients are misdiagnosed as suffering from unipolar depression. In a study of outpatients in a psychiatric clinic, over one third of patients with a history of mania or hypomania had been misdiagnosed as having unipolar depression.¹¹ The consequences of this misdiagnosis were serious—55% of those prescribed antidepressants developed a manic/hypomanic episode, and 23% developed rapid cycling.¹¹

The clinical course of bipolar disorder is pernicious. In patients with bipolar disorder, rates of suicide attempts have been estimated to range from 25% to 50%; the rate of suicide completion, based on a meta-analysis of 10 studies, is 19%, although rates vary considerably among studies (12%–60%).¹² It has been calculated that patients spend one fifth of their lives in an episode of illness.¹³ Patients who are misdiagnosed as depressed and treated with antidepressants may experience rapid cycling and/or mania. Rapid cycling (4 or more mood episodes during the previous 12 months) occurs in 5% to 20% of patients with bipolar disorder.¹⁴

DIAGNOSING BIPOLAR DISORDER

The diagnosis of bipolar disorder requires a clinical evaluation, including a mental status examination and psychiatric history. The clinician must inquire about past episodes of mania, hypomania, and mood swings. Identifying high-risk patients may save the busy clinician valuable time. One method to identify high-risk patients is to screen for bipolar disorder, particularly among patients with depression.

The Mood Disorder Questionnaire (MDQ) (Appendix 1)¹⁵ is a screening instrument for bipolar disorder that can easily be utilized in primary care settings. The MDQ has both good sensitivity and very good specificity.¹⁵ The MDQ can correctly identify 7 of 10 patients with bipolar disorder, while 9 of 10 patients without bipolar disorder would be correctly screened out. The MDQ includes 13 questions plus items assessing clustering of symptoms and functional impairment. The MDQ can provide primary care physicians with a quick and easy way to identify patients most likely to have bipolar disorder.

If the patient screens positive on the MDQ, the physician should proceed with a full clinical evaluation for bipolar disorder. Probing based on the MDQ responses may be helpful in guiding questions. Appropriate laboratory testing includes thyroid function tests and liver function tests.

Psychiatric Referral

When should primary care physicians refer patients suspected of having bipolar disorder to psychiatrists? Patients with current or past psychotic symptoms, those who are at risk for suicide or harm to others, and those whose symptoms are so severe that they may require hospitalization should be referred to a psychiatric specialist.

Follow-Up

Psychiatrists often are the initiators of treatment for bipolar disorder. Follow-up may be done by either the psychiatrist or the primary care physician. Patient and family education can help substantially with compliance and vigilance for early detection of relapse.

Appendix 1

The Mood Disorder Questionnaire

See also Editorial on page 7.