Mental Disorders Due to Another Medical Condition
General medical conditions can cause or be associated with a wide range of mental disorders. The psychiatrist should always remain vigilant for: (1) another underlying medical condition that the patient may have, and (2) illicit substances or medications that the patient may be taking.
Possible causes of psychiatric symptoms include:
• Neurological conditions: epilepsy, brain tumors, head trauma, and demyelinating diseases such as multiple sclerosis and amyotrophic lateral sclerosis (ALS).
• Infectious diseases affecting the brain: herpes simplex infection, neurosyphilis, HIV, Lyme disease, and prion diseases.
• Autoimmune diseases: such as systemic lupus erythematosus (SLE).
• Endocrine disorders: diseases of the thyroid, parathyroid glands, adrenal glands, and pituitary gland.
• Metabolic disorders: hepatic encephalopathy, uremic encephalopathy, hypoglycemic encephalopathy, diabetic ketoacidosis, and acute intermittent porphyria.
• Nutritional disorders: including deficiencies of niacin, vitamin B1 (thiamine), and vitamin B12.
• Toxic exposures: poisoning with substances such as mercury, lead, manganese, and arsenic.
References:
Kaplan & Sadock: Synopsis of Psychiatry, twelfth edition
Kaplan & Sadock: Pocket Handbook of Clinical Psychiatry, fifth edition;
American Psychiatric Association: Diagnostic Manual of Mental Disorders, 1994;
Robert J. Waldinger: Psychiatry for Medical Students, third edition, translated by Anastas Suli.