Symptoms and their severity can vary. A person with bipolar disorder may have distinct manic or depressed states but may also have extended periods—sometimes years—without symptoms. A person can also experience both extremes simultaneously or in rapid sequence.
Severe bipolar episodes of mania or depression may include psychotic symptoms such as hallucinations or delusions. Usually, these psychotic symptoms mirror a person’s extreme mood. People with bipolar disorder who have psychotic symptoms can be wrongly diagnosed as having schizophrenia.
Mania. To be diagnosed with bipolar disorder, a person must have experienced at least one episode of mania or hypomania. Hypomania is a milder form of mania that doesn’t include psychotic episodes. People with hypomania can often function well in social situations or at work. Some people with bipolar disorder will have episodes of mania or hypomania many times throughout their life; others may experience them only rarely.
Although someone with bipolar may find an elevated mood of mania appealing—especially if it occurs after depression—the “high” does not stop at a comfortable or controllable level. Moods can rapidly become more irritable, behavior more unpredictable and judgment more impaired. During periods of mania, people frequently behave impulsively, make reckless decisions and take unusual risks.
Most of the time, people in manic states are unaware of the negative consequences of their actions. With bipolar disorder, suicide is an ever-present danger because some people become suicidal even in manic states. Learning from prior episodes what kinds of behavior signals “red flags” of manic behavior can help manage the symptoms of the illness.
Depression: The lows of bipolar depression are often so debilitating that people may be unable to get out of bed. Typically, people experiencing a depressive episode have difficulty falling and staying asleep, while others sleep far more than usual. When people are depressed, even minor decisions such as what to eat for dinner can be overwhelming. They may become obsessed with feelings of loss, personal failure, guilt or helplessness; this negative thinking can lead to thoughts of suicide.
The depressive symptoms that obstruct a person’s ability to function must be present nearly every day for a period of at least two weeks for a diagnosis. Depression associated with bipolar disorder may be more difficult to treat and require a customized treatment plan.
Scientists have not yet discovered a single cause of bipolar disorder. Currently, they believe several factors may contribute, including:
- The chances of developing bipolar disorder are increased if a child’s parents or siblings have the disorder. But the role of genetics is not absolute: A child from a family with a history of bipolar disorder may never develop the disorder. Studies of identical twins have found that, even if one twin develops the disorder, the other may not.
- A stressful event such as a death in the family, an illness, a difficult relationship, divorce or financial problems can trigger a manic or depressive episode. Thus, a person’s handling of stress may also play a role in the development of the illness.
- Brain structure and function. Brain scans cannot diagnose bipolar disorder, yet researchers have identified subtle differences in the average size or activation of some brain structures in people with bipolar disorder.