Like all psychiatric illnesses, bipolar disorder is multifactorial, and includes a genetic risk factor.
Studies of twins and families have shown that people with a first-degree relative (a parent or a sibling) with bipolar disorder have a higher risk of developing this disorder themselves, compared to the general population.
However, genetics is just one of many factors that increase the chances of developing bipolar disorder, and other environmental and neurobiological factors can also play a role.
More than one gene involved in bipolar disorder
It is likely that, rather than a single bipolar gene, there are many different genes, all linked to a very small increase in risk. On the other hand, we also know that overall heritability (the degree of risk attributed to genetic factors) is an important factor – probably between 60 and 85%.
Having relatives with bipolar disorder significantly increases the risk of developing the disease yourself (up to 10 times higher for first-degree relatives).
When a patient is diagnosed, a history of bipolar disorder or suicide in the family must always be checked.
Environmental factors in bipolar disorder
As well as environmental factors, there are also epigenetic factors, which are environmental factors that change the expression of certain genes, and may be responsible for bipolar disorder.
Stress
Stress can trigger mania or depression in some patients with bipolar disorder. Stressful life events such as relationship problems, financial difficulties, or major life changes can trigger a bipolar episode.
Traumatic events
Traumatic events during childhood or adulthood, such as physical, sexual or emotional abuse, may increase the risk of developing bipolar disorder.
Substance abuse
Excessive drug or alcohol consumption can aggravate the symptoms of bipolar disorder and make treatment more difficult.
Changes in sleep patterns
Sleep-wake cycle disruptions, such as lack of sleep or changes in circadian rhythm, can trigger manic or depressive episodes in people with bipolar disorder
Major life events
Events like bereavement, losing your job, moving home or other major life changes can impact emotional balance and trigger manic or depressive episodes.
It is important to know that bipolar disorder is usually caused by a complex combination of genetic, environmental and neurobiological factors, and that these factors can vary from person to person.
