Paranoid schizophrenia is one of several types of schizophrenia, a chronic mental illness in which reality is interpreted abnormally (psychosis). The classic features of paranoid schizophrenia are having beliefs that have no basis in reality (delusions) and hearing things that aren't real.

What is it?

Paranoid schizophrenia is one of several types of schizophrenia, a chronic mental illness in which reality is interpreted abnormally (psychosis). The classic features of paranoid schizophrenia are having beliefs that have no basis in reality (delusions) and hearing things that aren't real (auditory hallucinations).

With paranoid schizophrenia, your ability to think and function in daily life may be better than with other types of schizophrenia. You may not have as many problems with memory, concentration or dulled emotions. Still, paranoid schizophrenia is a serious, lifelong condition that can lead to many complications, including suicidal behavior. But with effective treatment, you can manage the symptoms of paranoid schizophrenia and work toward leading a happier, healthier life.


Signs and symptoms of paranoid schizophrenia may include:

  • Auditory hallucinations, such as hearing voices
  • Delusions, such as believing a co-worker wants to poison you
  • Anxiety
  • Anger
  • Aloofness
  • Violence
  • Verbal confrontations
  • Patronizing manner
  • Suicidal thoughts and behavior

With paranoid schizophrenia, you're less likely to be affected by mood problems or problems with thinking, concentration and attention. Instead, you're most affected by what are known as positive symptoms.


It's not known what causes paranoid schizophrenia. However, a growing body of evidence suggests that paranoid schizophrenia and other forms of schizophrenia are caused by brain dysfunction. Why and how that brain dysfunction occurs is still under investigation, though.

It's thought that an interaction of genetics and environment may lead to brain dysfunction that causes paranoid schizophrenia. Problems with certain naturally occurring brain chemicals called neurotransmitters may also contribute to paranoid schizophrenia. Imaging studies show differences in the brain structure of people with schizophrenia, but researchers aren't yet sure about the significance of these changes.

Risk factors

Although the precise cause of paranoid schizophrenia isn't known, researchers have identified certain factors that seem to increase the risk of developing or triggering paranoid schizophrenia, including:

  • Having a family history of schizophrenia
  • Exposure to viruses while in the womb
  • Malnutrition while in the womb
  • Stressful life circumstances
  • Trauma or abuse during childhood
  • Older paternal age
  • Taking psychoactive drugs during adolescence

According to the National Institute of Mental Health, schizophrenia affects about 1 percent of the general population, and paranoid schizophrenia affects an even smaller percentage. Schizophrenia typically becomes apparent between the teenage years and the mid-30s, but paranoid schizophrenia may start later in life.


Left untreated, paranoid schizophrenia can result in severe emotional, behavioral, health, and even legal and financial problems that affect every area of your life. Complications that paranoid schizophrenia may cause or be associated with include:

  • Suicidal thoughts and behavior
  • Self-destructive behavior
  • Depression
  • Abuse of alcohol, drugs or prescription medications
  • Poverty
  • Homelessness
  • Incarceration
  • Family conflicts
  • Inability to work or attend school
  • Health problems from antipsychotic medications
  • Being a victim or perpetrator of violent crime
  • Heart and lung disease related to smoking


If your doctor believes you may have paranoid schizophrenia or another mental illness, he or she typically runs a series of medical and psychological tests and exams. These can help pinpoint a diagnosis, rule out other problems that could be causing your symptoms and check for any related complications.

These exams and tests generally include:

  • Physical exam. This may include measuring height and weight, checking vital signs, such as heart rate, blood pressure and temperature, listening to your heart and lungs, and examining your abdomen.
  • Laboratory tests. These may include a complete blood count (CBC), screening for alcohol and drugs, and a check of your thyroid function.
  • Psychological evaluation. A doctor or mental health provider will talk to you about your thoughts, feelings and behavior patterns. He or she will ask about your symptoms, including when they started, how severe they are, how they affect your daily life and whether you've had similar episodes in the past. You'll also discuss any thoughts you may have of suicide, self-harm or harming others. Your doctor may also want to talk to family or friends, if possible.

Diagnostic criteria for paranoid schizophrenia

To be diagnosed with paranoid schizophrenia, you must meet the symptom criteria.

Diagnostic criteria for paranoid schizophrenia include:

  • A preoccupation with one or more delusions
  • Frequent auditory hallucinations

It can sometimes be difficult to diagnose paranoid schizophrenia, especially because other conditions may have similar symptoms. Be sure to stick with it, though, so that you can get appropriate treatment.