Bipolar disorder is often put together with “classic” depression . Understandably so, because a persistent low mood is often a major part of bipolar disorder, and it is not uncommon for bipolar disorder to be misdiagnosed with unipolar depression. These periods are known as “mania” or “hypomania” (a milder form of mania), hence the previous name of “manic depression” for bipolar disorder. Bipolar disorder, however, differs in that periods of extremely elevated mood also present themselves. A less severe form of bipolar disorder is called “cyclothymic disorder”.
Delusional thinking, sleep disturbances before the onset of a manic or depressive episode, impulsive decision-making and periods of extreme excitement and energy followed by extremely low moods are classic hallmarks of bipolar disorder. Hallucinations and even psychosis are also possible with bipolar disorder. Bipolar disorder is often divided into three types:
- Bipolar I disorder – at least one manic episode, with or without depressive episodes
- Bipolar II disorder – at least one hypomanic episode and one major depressive episode, but not any manic episode
- Cyclothymic disorder – less severe symptoms of bipolar disorder, but presenting over a longer period of time
The precise cause of manic depression is not known, but it is thought that genetics, a history of abuse, long-term stress and suffering significant hardship are all contributing factors. Conditions such as traumatic brain injury (TBI), ADHD, multiple sclerosis (MS) and HIV infection may also present symptoms similar to bipolar disorder. Personality disorders, substance misuse disorder, and schizophrenia may also present themselves similarly.
Polymorphisms in BDNF, DRD4, DAO and TPH1 genes have been implicated in the developments of bipolar disorder. As for signaling pathways implicated in the development of bipolar disorder, they include: CRH, cardiac β-adrenergic, Phospholipase C, glutamate receptor, cardiac hypertrophy, Wnt, Notch, and endothelin 1 signaling pathways. Many people with bipolar disorder tend to have at least one relative with the same disorder, suggesting a genetic link.
Bipolar disorder affects approximately 1%-3% of the global population, with approximately 2.6% of US citizens (5.7 million) suffering from bipolar disorder. Symptoms usually arise from the age of 25 onwards, and seems to affect males and females equally. In 1991, it was estimated that bipolar disorder cost the United States $45 billion. Those with bipolar disorder are more likely to die from heart disease, and are at higher risk of suicide.
Due to the difference between depression and bipolar disorder, antidepressants are contraindicated for people suffering from bipolar disorder during a manic episode. However, antidepressants may still be used during the depressive periods, but these must be carefully monitored, as using them during a manic/hypomanic episode can worsen the condition. Hence, benzodiazepines, anticonvulsants, mood stabilizers (e.g. lithium) and antipsychotics are often used as well for those with bipolar disorder. Therapy, regulated sleeping patterns, exercise, regimented activity and following a healthy diet are also helpful.