Transporter psychosis was an incurable medical condition. It was caused by a breakdown of neurochemicals during transport, affecting the body's motor functions, autonomic systems and the higher reasoning centers of the brain. A victim of transporter psychosis suffered from paranoid delusions, multi-infarct dementia, hallucinations (somatic, tactile, and visual), and psychogenic hysteria. Peripheral symptoms included sleeplessness, accelerated heart rate, diminished eyesight leading to acute myopia, painful spasms in the extremities, and, in most cases, dehydration. (TNG: "Realm of Fear" )