Bipolar Disorder

Course

The course of bipolar disorder is dependent on a number of factors, such as the severity of the illness, the age of onset, comorbid conditions, frequency of episodes, cycle pattern and the presence or absence of 'rapid cycling'.

Frequency of Episodes

The time between the first, second and third episodes is much greater than that between subsequent episodes. After the first three episodes there is a general increase in frequency and relative stabilisation (Suppes et al, 2000). There is a sub-group of patients who experience four or more mood episodes per year and this is termed 'rapid cycling'. Occurring in 5–20% of adults with bipolar disorder, rapid cycling is more common in women than men. In one study 72% of women compared with 28% of men experienced rapid cycling (Suppes et al, 2000). Bipolar disorder with an onset in adolescence is often rapid cycling with stabilisation of periods occurring over time.

Cycling

Some patients have a well-established cycle pattern – moving from depression to mania or mania to depression, while other patients have a varied and unpredictable pattern. The cycle of episodes may have an affect on the course of the illness, as there is some evidence that patients with a mania to depression pattern respond better to pharmacological treatment with mood stabilisers than patients with a depression to mania pattern (Suppes et al, 2000).

Mixed Epsiodes

A mixed episode is defined by sufficient depressive and manic symptoms occurring simultaneously, such that both diagnostic criteria are met. The effect that this concurrency of symptoms has on the course of bipolar disorder is unclear. Some research suggests that patients with mixed episodes take longer to recover from an episode and have poorer outcomes than those who experience pure mania or hypomania. Mixed episodes are associated with an increased incidence of substance abuse and suicide ideation and attempts (Suppes et al, 2000). In addition, manic episodes that occur in adolescence and early adulthood may be more likely to be mixed episodes.

Age of Onset

The majority of bipolar patients will experience their first symptoms before the age of 25 years; earlier if there is a family history of affective disorder (Bland, 1997; Suppes et al, 2000). However, in many cases, depressive episodes will usually precede a manic episode (Marnevos & Angst, 2000). A particularly early age of onset is often associated with a more severe course of illness; this may be related to the number and severity of the depressive episodes. The early onset of depressive episodes has also been associted with an increase in the risk (Suppes et al, 2000).

Comorbid Conditions

The lifetime prevalence rates of other psychiatric and medical conditions are greatly increased in patients with bipolar disorder and these comorbid conditions can make the course of the illness more difficult to treat and manage (Suppes et al, 2000). The two most common comorbid conditions are anxiety disorder and substance abuse; the National Comorbidity Study in 1999 reported a prevalence of 93% for anxiety disorder and of 64% for substance abuse in patients with bipolar I disorder (Marnevos & Angst, 2000). Patients with bipolar disorder and comorbid anxiety disorder experience a more severe course of disease than those without comorbid anxiety. Patients with bipolar disorder who also have a history of substance abuse have a more complicated disease course than those with no history of substance abuse (Suppes et al, 2000).

Find out more about comorbid conditions.

Suicide

Suicide is one of the major causes of increased mortality in patients with mood disorders, and patients with bipolar disorder are at higher risk of committing suicide than patients with other psychiatric disorders. The lifetime prevalence of suicide in bipolar disorder patients is 15% compared with 6% in mood disorder patients. Most studies on the suicide risk of patients with bipolar disorder have enrolled severely ill, hospitalised patients, this results in a sampling bias and means that the actual rate of suicide in the overall bipolar population may be lower. The Epidemiologic Catchement Area Study showed that 25–50% of patients with bipolar disorder attempt suicide at least once in their lifetime, and that patients often showed detailed planning and a resolute intent to die. Increased risk of suicide is associated with past suicide attempts, alcohol abuse and the length of time elapsed after hospital discharge. Women attempt suicide 2–3 times more often than men, but generally use less lethal means (Jamison, 2000).

Other Factors

Other factors that can influence the course of bipolar disorder include: stress; lifestyle; the sleep-wake schedule; the use of substances and alcohol and the long-term use of prescription medication (Suppes et al, 2000).