Paranoia is an overwhelming feeling of fear and suspicion which manipulates a person’s thoughts and behavior. The causes of paranoia can be mental and physical illnesses as well as prescription and illegal drugs. Treatment for paranoia is anti-psychotic or anti-depressant drugs and psychotherapy.

The most common mental illnesses which can produce paranoia are paranoid schizophrenia, paranoid personality disorder, and Alzheimer’s disease. Paranoid schizophrenia is a form of mental illness marked by psychosis or difficulty interpreting reality. This psychosis can cause people to misinterpret the actions of people around them, producing paranoid thoughts and behavior. Paranoid personality disorder is a psychiatric illness marked by continual feelings of suspicious and anxieties. Alzheimer’s disease is a progressive form of dementia which impacts memory and rational thought processes, and sometimes patients feel and act strongly suspicious of caregivers and family members.

Other causes of paranoia are Parkinson’s disease, Huntington disease, strokes, and brain injuries. Parkinson’s disease is a neurological disorder leading to uncoordinated movement and shaking. The medication used to treat Parkinson’s disease will sometimes cause paranoid thoughts or behavior, and switching medication or manipulating the dose may help to control this side effect. Huntington’s disease is a degenerative neurological disorder which can produce paranoia as the brain loses the ability to reason. Rare causes of paranoia include stroke and brain injury, both of which can produce either temporary periods of or lasting problems with paranoia.

Several prescription medications such as the acid reflux medication cimetidine, the muscle relaxer baclofen, some corticosteroids, amphetamines, antidepressants, and medications used to treat the human immunodeficiency virus can be causes of paranoia. In most cases when paranoia manifests, the dose of the drug can be altered to control the paranoid side effect or a different drug can be substituted. One of the most well known causes of paranoia is the use of the illegal drugs 3,4 methylenedioxymethamphetamine or ecstasy, marijuana, lysergic acid diethylamide (LSD), phencyclidine (PCP), and amphetamines. Withdrawal from these drugs may also cause difficult periods of paranoia.

Treatment for paranoia will often involve the use of anti-psychotic or anti-depressant medications. When possible, psychotherapy can be tried for receptive patients, but the omnipotent fear and suspicious thoughts of paranoid people may prevent this form of therapy from working. Psychotherapy is sometimes possible after taking anti-psychotic or anti-depressant medications for a short period of time. In more severe cases, paranoia may be treated with electroconvulsive therapy or hospitalization.