Psychosis, on the other hand, is not a response to a specific traumatic event. It develops out of a combination of biological, psychological, and environmental factors. Some people are genetically predisposed to psychosis. There is no clear, identifiable, single cause for psychosis. The symptoms, however, can be similar in some ways to PTSD. Psychosis sufferers experience hallucinations, and can be withdrawn and emotionally disengaged from everyone around them. Veterans with PTSD may display psychotic symptoms, including paranoia and delusions.
PTSD can be treated with psychotherapy, medication, or a combination of both. Psychosis almost always requires medication, and psychotherapy by itself is not effective in relieving symptoms of psychosis.