The diathesis–stress model is a psychological theory that explains behavior as a result of both biological and genetic vulnerability (the meaning of the greek word diathesis), and stress from life experiences. This model thus assumes that the onset of a certain disorder may result from a combination of one’s biological disposition towards the given disorder and stressful events that bring about the onset to such disorder. The term “diathesis” is used to refer to a genetic predisposition toward an abnormal or diseased condition. According to the model, this predisposition, in combination with certain kinds of environmental stress, results in abnormal behavior. This theory is often applied to mental disorders, like schizophrenia, depression, and anxiety disorder.
Schematic of diathesis–stress model
Historical development
The diathesis concept has a long history in medical terminology. The word diathesis derives from the ancient Greek idea of disposition here. This word was related to the humor (body fluids) theory of temperament and disease. The peculiar terminology diathesis-stress was used by psychologists Manfred Bleuler and David Rosenthal in the 1960s with the development of new theories about schizophrenia.
Current formulation
In the diathesis–stress model, a biological or genetic vulnerability or predisposition (diathesis) interacts with the environment and life events (stressors) to trigger behaviors or psychological disorders. The underlying dynamic within the model between the diathesis and the stress components is not clear. For some authors, it is likely to be additive or ipsative (e.g. the greater the underlying vulnerability, the less stress is needed to trigger the behavior or disorder; and convertly); but other view hold that high levels of both stress and diathesis are needed, or that diatheses are changed under high stress to allow further less stressful events to stress sufficiently the diathesis and trigger the onset of the disease.
Effects
This model has had profound benefits for people with severe and persistent mental illnesses. It has stimulated research on the common stressors that people with disorders such as schizophrenia experience. More importantly, it has stimulated research and treatment on how to mitigate this stress, and therefore reduce the expression of the diathesis, by developing protective factors, which include rigorous and nuanced psychopharmacology, skill building (especially problem solving and basic communication skills), and the development of support systems for individuals with these illnesses.
Even more importantly, the stress–vulnerability–protective factors model has allowed mental health workers, family members, and clients to create a sophisticated personal profile of what happens when the person is doing poorly (the diathesis), what hurts (the stressors), and what helps (the protective factors). This has resulted in more humane, effective, efficient, and empowering treatment interventions.