There are a number of factors involved in the onset of mental disorders which cannot be considered in isolation: biology (including genetics and epigenetics), psychology, environment, context, life circumstances, personal history, and social factors all play a role in the onset and development of disorders. All these factors interact: environmental parameters can sometimes cause disorders that have biological consequences.
Is Depression Hereditary?
Depression is not an inherited disease, it is not transmitted. However, there is a predisposition to develop this disorder in people with genetic variants, most of which are still unknown today. This predisposing genetic component partly explains familial cases. It is estimated that a person with one parent who has experienced a major depressive episode (MDE) is two to four times more likely to be depressed than the general population.
This predisposition is associated with an environmental “trigger” factor that is very often a situation of intense stress, such as the death of a loved one, a break-up, or a situation of social exclusion, such as a job loss.
Depression is often characterized by multiple major depressive episodes, spaced out over time. The risk of relapse after a first MDE is estimated at 60%, rising to 90% after the third episode.
