Classified as a "conversion disorder" by the DSM-IV, a psychogenic disease is a condition in which mental stressors cause physical symptoms which may or may not match another known physical disorder. The manifestation of physical symptoms without biologically identifiable cause results from disruptions in normal brain function due to psychological stress. During a psychogenic episode, neuroimaging has shown that neural circuits affecting functions such as emotion, executive functioning, perception, movement, and volition are inhibited. These disruptions become strong enough to prevent the brain from voluntarily allowing certain actions (e.g. moving a limb). When the brain is unable to signal to the body to perform an action voluntarily, physical symptoms of a disorder arise. Examples of diseases that are deemed to be psychogenic in origin include psychogenic seizures, psychogenic polydipsia, psychogenic tremor, and psychogenic pain.
The term psychogenic disease is often used similarly to psychosomatic disease. However, the term psychogenic usually implies that psychological factors played a key causal role in the development of the illness. The term psychosomatic is often used more broadly to describe illnesses with a known medical cause where psychological factors may nonetheless play a role (e.g., asthma as exacerbated by anxiety).
