The diathesis-stress model of depression describes the etiology of depression in terms of the linkage between biological vulnerability and environmental factors. The model assumes that people have different levels of sensitivity for developing depression. In the language of this model, these sensitivities are referred to as diatheses. Diatheses include biological and sociocultural factors. Some people may have more of these factors for developing depression than other people. This model suggests that having a biological sensitivity towards developing depression by itself is not enough to cause the condition. Instead, a person's sensitivities must interact with stressful life events to lead to the condition. Death, relationship difficulties, normal milestones such as puberty, marriage, or retirement are examples of stressful life events.
According to this model, the greater a person's biological vulnerability for developing depression, the less environmental stress is needed to cause him or her to become depressed. If someone has a smaller amount of sensitivity for becoming depressed, it will take higher levels of stress for the condition to happen. Until people reach this critical amount of stress, they will generally live their lives normally. Their sensitivity is considered to be hidden.
This model has received empirical support. For instance, Arnau-Soler et al. (2019) concluded that gene and environment interaction plays a role in the etiology of depression.
Similarly, Patten (2013) empirically tested the diathesis-stress model and concluded that it is valid.
Overall, according to the diathesis-stress model, sociocultural factors can explain depression when combined with a biological vulnerability.