Bipolar disorder---sometimes called manic-depressive disorder---is a chronic condition characterized by extreme high and low swings in mood. Though it can develop at any age, from childhood through late adulthood, it most commonly appears between the ages of 15 and 30, according to the University of Maryland Medical Center. People exposed to a combination of inherited, biological and environmental risk factors are at greater risk for developing bipolar disorder.
Genetics
Bipolar disorder often runs in families. According to the National Institute of Mental Health, while most people with a family history of bipolar disorder will not develop the condition, those with a genetic predisposition are up to six times more likely to develop bipolar disorder compared with those who have no familial link. Exactly how these gene abnormalities cause bipolar disorder is not known; however, they likely influence brain chemistry, neurotransmitter function and/or hormones in a way that adversely affects and destabilizes mood, according to the Mayo Clinic.
Congenital genetic mutations may also increase a person's risk for developing bipolar disorder. According to the University of Maryland Medical Center, early research suggests that the older a father's sperm at the time of his baby's conception, the more likely the fetus will suffer from genetic mutations that increase its likelihood of developing bipolar disorder. More research is needed to confirm and expand upon these findings.
Stress and Triggering Events
According to the National Institute of Mental Health, research on twins with a family history of bipolar disorder reveals that---in spite of their identical genes---one twin can develop the disorder, while the other will remain symptom free. To explain these findings, researchers hypothesize that environmental factors interact with genetics to ultimately determine whether bipolar disorder will develop.
These environmental factors may come in the form of stressful life events that can trigger the onset of symptoms among those with a genetic predisposition. According to the Mayo Clinic, chronic or sudden stress brought on by career, the death of a loved one, an unexpected move or other major life change may all increase the risk for developing symptoms of bipolar disorder.
According to MedlinePlus, recreational drug use or the use of steroids or certain antidepressant medications can trigger a manic episode among certain people. Persistent insomnia and other dramatic life changes such as childbirth and parenthood are also risk factors that may trigger the onset of mania.
Co-Occurring Psychological and Physical Health Conditions
According to the Mayo Clinic, people with certain physical and/or mental health problems are more likely to have bipolar disorder. For example, those who are obese or who have cardiovascular or thyroid problems are at increased risk of the condition. Post-traumatic stress disorder, generalized anxiety disorder, social phobia, substance abuse and attention deficit hyperactivity disorder are also risk factors for bipolar disorder.
According to the University of Maryland Medical Center, stroke and other vascular and neurological conditions increase the risk for developing bipolar disorder later in life.
