While we don’t yet know exactly what causes bipolar disorder, we do know that it appears to have primarily biological underpinnings. However, its onset is often linked to a stressful life event.
And while the causes of bipolar disorder are still unknown, there are a number of factors that are believed to play a role, including genetics, brain chemicals, environmental factors and sometimes medical illnesses.
Bipolar disorder is frequently inherited, with genetic factors accounting for approximately 80% of the cause of the condition.
If one parent has bipolar disorder, there is a 10 per cent chance that his or her child will develop the illness. If both parents have bipolar disorder the likelihood of their child developing the illness rises to 40 per cent.
However, just because one family member has the illness, it is not necessarily the case that other family members will also develop the illness. Other factors also come into play.
A recent theory about the cause of bipolar disorder is that it is related to abnormal serotonin chemistry in the brain. Serotonin is one of the neurotransmitters in the brain, and one that strongly affects a person’s mood. It is thought that abnormal serotonin chemistry causes mood swings because of its feedback effect on other brain chemicals. It is unlikely, however, that serotonin is the only neurotransmitter involved.
While the onset of bipolar disorder may be linked to a stressful life event, it is unlikely that stress itself is a cause of bipolar disorder. Notwithstanding this, people who suffer from bipolar disorder often find it beneficial to find ways of managing and reducing stress in their lives (as do people without the disorder!).
Again – while not a cause – seasonal factors appear to play a role in the onset of bipolar disorder, with the chance of onset increasing in spring. The rapid increase in hours of bright sunshine is thought to trigger depression and mania by affecting the pineal gland.
Medical illness is not a cause of bipolar disorder, but in some instances can cause symptoms that could be confused with mania or hypomania. Some medications and certain illicit stimulant drugs can also cause manic and hypomanic symptoms.
Antidepressants can trigger manic or hypomanic episodes in susceptible people it is important to report any unusual symptoms to your prescribing doctor while on these medications.
For women who are genetically or otherwise biologically predisposed to developing bipolar disorder, the postnatal period can coincide with a first episode of bipolar disorder.
Like any other medical condition, such as heart disease or diabetes, bipolar disorder is an illness that requires careful management.
While there is no known cure for bipolar disorder, the good news is that its severity and the frequency of episodes can be reduced or prevented with medication and other supports, such as psychological therapies.