Psychosis Due to a Medical Condition. This diagnosis is made when a patient's medical history, physical examination, or laboratory test results suggest that one or more medical conditions have caused brain changes that might create psychotic symptoms, and those psychotic symptoms (e.g., hallucinations, delusions) are in fact present since the medical condition has occurred. A surprisingly large number of different medical conditions are capable of creating psychosis. Neurological conditions that may cause psychosis include brain tumors, cerebrovascular disease, Huntington's disease, multiple sclerosis, epilepsy, auditory or visual nerve injury or impairment, deafness, migraine, and infections of the central nervous system. Endocrine disturbances include increases or decreases in the activity of the thyroid, parathyroid, or adrenocortical system. A decrease in blood gases such as oxygen or carbon dioxide or imbalances in blood sugar or electrolytes are some metabolic causes of psychosis. Finally, autoimmune disorders with central nervous system involvement such as systemic lupus erythematosus have also been known to cause psychosis.
Psychosis caused by a medical condition may be a single isolated incident or may be recurrent, cycling with the status of the underlying medical condition. Although treating the medical condition often results in the remission of the psychosis, this is not always the case. Psychotic symptoms may persist long after the medical conditions that have caused them are cured.
The following diagnostic criteria must be met before a diagnosis of Psychosis Due to a Medical Condition is warranted, according to the DSM-IV-TR:
A) Prominent hallucinations or delusions
B) There is evidence from the history, physical examination, or laboratory findings that the disturbance is the direct physiological consequence of a general medical condition
C) The disturbance is not better accounted for by another medical disorder
D) The disturbance does not occur exclusively during the course of a delirium