There are paranoid delusions of jealousy, persecution, someone is after them, someone is trying to kill them, or poison them. Hallucinations are internal impulses projected onto images in the real world. Most common is hearing voices. Some see things that are not there. Some researchers think that it is the result of problems with the chemical neurotransmitter dopamine.
Doctors prescribe anti-psychotic mediation.
Physical Much abnormal behavior is do the result of dealing with stress. Psychological factors can affect your health. Stress can cause headaches, allergies, asthma, diarrhea, ulcers. Somatoform disorder is marked by bodily complaints that have no physical explanation. Physical problems can also cause mental disorders.