It can be really tough to tell the difference between major (or unipolar) depression and bipolar disorder in many cases. In part, because people will seek care for symptoms of depression, but may not for symptoms of mania, particularly the milder form of mania, called hypomania. So, clinicians see and record only depression.
Because diagnosis of bipolar disorder requires documentation of at least one manic or hypomanic episode, cases of bipolar disease may be misdiagnosed as unipolar depression.
Is it depression or bipolar?
One study by Das and colleagues, “Screening for bipolar disorder in primary care practice” (JAMA 2005;293(8):956), documented that the majority of people who screened positive for bipolar disorder had sought care for their symptoms, but had been misdiagnosed as having depression and/or anxiety.
Another study by Manning et al, “On the nature of depressive and anxious states in a family practice setting: the high prevalence of bipolar II and related disorders in a cohort followed longitudinally” (Comprehensive Psychiatry 1997;38(2):102), found that 26% of cohort of 108 consecutive anxious and/or depressed patients in a family practice setting actually had bipolar disorder.
The spectrum of mood disorders
The spectrum or poles of mood disorders range from depression without mania (major depression) through Bipolar 2 (episodes of depression with at least one episode of hypomania) to Bipolar 1 (episodes of depression and at least one manic episode).
The prevailing mood of many folks with Bipolar 1 is serious depression. This is not feeling a bit blue because things aren’t going well in your life. Rather it is a depression associated with many physical (somatic) symptoms, such as major changes in appetite, sleep disturbances, loss of energy or fatigue, and loss of interest in things that used to bring pleasure (e.g., sex, relationships, food).
People have difficulty concentrating or making decisions so depression can have a major impact on activities of daily life, including work. Finally, people with major depression may think about, plan, or actually carry out suicide attempts.
People with Bipolar 1 disorder also have a history of at least one episode of mania characterized by symptoms polar opposite of depression:
- Diminished need for sleep
- Excessive talking or pressured speech
- Racing thoughts or flight of ideas
- Clear evidence of distractibility
- Increased level of goal-focused activity at home, at work, or sexually
- Excessive pleasurable activities, often with painful consequences
People experiencing mania may not recognize the symptoms as pathological. As in many cases, they perceive the state as pleasurable, one where they are in control of their lives, powerful and able to achieve anything they want.
The episode is usually brought to the attention of health care professionals when it results in something dramatic, like being arrested or hospitalized—or when family members or friends end up forcing the person to get medical attention.
The episodes of mania in Bipolar 2 are much more subtle than in Bipolar 1 and therefore even more likely to be missed. People may experience the hypomania as just having more energy than usual, being more creative or more in control. These symptoms may not get people into as much trouble as full-blown mania, so may be forgotten or ignored by both the person with the symptoms and their family members.
Other forms of bipolar disorder
Cyclothymic disorder is characterized by mood swings that don’t meet the criteria for major depression or mania or hypomania. “Other Specified Bipolar” is a catchall diagnosis when symptoms don’t meet the criteria for the other forms.
Clues to the diagnosis
The fact that diagnosis may be delayed by 7 to 10 years lets you know that, in some cases, making the diagnosis of Bipolar disorder can be challenging.
Since depression typically precedes episodes of mania by about the same period of time, it may be almost impossible to correctly categorize someone with depression as Bipolar instead of Major Depression. There are some approaches that may help.
First of all, there are some screening tools, such as the self-administered Mood Disorder Questionnaire and the M3, the latter being a 3-minute screen that is available online. There is also the clinician-administered World Health Organization Composite International Diagnostic Interview 3.0 (or CIDI).
Screening positive for Bipolar disorder using these tools should prompt a visit to a doc or other clinician familiar with diagnosing and treating the condition.
Personal and family history
A detailed personal and family history of mood disorder symptoms should be explored. When did the symptoms first start?
More than half of people with Bipolar disorder report having symptoms, usually depression, as early as their teenage years. At least half of all cases start before age 25. Many of the patients with Bipolar I disorder on Patients Like Me describe having had their first symptoms at quite a young age.
Bipolar disorder also tends to run in families. Children with a parent or siblings with bipolar disorder are more likely to develop the illness—although most children with a family history will not develop the illness.
Because people with bipolar disease are more likely to seek care for symptoms of depression as opposed to mania, it is important to do a careful review of symptoms both with symptomatic persons as well as family members. Specifically ask about symptoms that are more common in bipolar disease than depression, such as hypersomnia (excessive sleepiness), hyperphagia (excessive hunger or increased appetite), mood lability, psychomotor retardation (slowing down of thoughts and reduced physical movement) and pathological guilt.
A detailed social history may reveal a history of multiple divorces, tempestuous interpersonal relationships, and romantic instability—all of which are features of Bipolar disorder as well as a rocky employment history and a history of financial, and even legal problems. Substance abuse, including abuse of multiple substances, is not uncommon.
An important clue, that may be overlooked, is the response to treatment. Patients that have failed to respond to three or more antidepressant trials for depression should be evaluated for bipolar disorder. Use of antidepressants without a mood stabilizer can trigger hypomania or mania, so this is another hint that the diagnosis is bipolar instead of unipolar mood disorder.
Why is early diagnosis important?
Bipolar disease can worsen if left undiagnosed and untreated. Not only can proper diagnosis and treatment help people with bipolar disease but it can lead to healthier and more productive lives. In most cases, treatment can help reduce the frequency and severity of episodes.
An additional concern is that some treatments for unipolar depression may actually worsen bipolar disorder unless a mood stabilizer such as lithium is given simultaneously.