Question: What causes bipolar disorder?
Answer: There's no single cause for bipolar disorder. Most experts agree that there are many causes, and they combine genetic, other biological causes, social causes, possible vulnerability, in a person who would have bipolar disorder.
Eighty to 90 percent of patients with bipolar disorder have the illness in their families. In identical twins, if one twin is ill, only 50 percent of other twins become ill. That means that 50 percent of the illness is environmental. There's a consensus that the illness is associated with chemical imbalance in the brain. That involves chemicals that are called neurotransmitters, and the most common ones disrupted are serotonin, dopamine and norepinephrine.
High-expressed emotion in the family, which is a combination of over-involvement and criticism in the affairs of others, is a risk factor for developing bipolar disorder. Other stress factors, like life-stressors, like for instance divorce, financial loses, job loses, or immigration can contribute to the onset of bipolar disorder. The important thing to know; is that what's inherited in bipolar disorder is not the illness itself, but vulnerability. And whether the person does or does not get the illness depends on what's happening in that person's life. Interventions, like medications or family interventions that would reduce stress and introduce structure in the life of a person who has bipolar illness in the family, could be very helpful and may prevent or delay the onset of the illness.