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Schizophrenia and Other Psychotic Disorders

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What Are the Symptoms of a Psychotic Disorder? continued...

Hallucinations are unusual sensory experiences or perceptions of things that aren't actually present, such as seeing things that aren't there, hearing voices, smelling odors, having a "funny" taste in your mouth, and feeling sensations on your skin even though nothing is touching your body.

Delusions are false beliefs that are persistent and organized, and that do not go away after receiving logical or accurate information. For example, a person who is certain his or her food is poisoned, even if it has been proven that the food is fine, is suffering from a delusion.

Other possible symptoms of psychotic illnesses include:

  • Disorganized or incoherent speech
  • Confused thinking
  • Strange, possibly dangerous behavior
  • Slowed or unusual movements
  • Loss of interest in personal hygiene
  • Loss of interest in activities
  • Problems at school or work and with relationships
  • Cold, detached manner with the inability to express emotion
  • Mood swings or other mood symptoms, such as depression or mania

What Causes Psychotic Disorders?

The exact cause of psychotic disorders is not known, but researchers believe that many factors may play a role. Some psychotic disorders tend to run in families, suggesting that the tendency, or likelihood, to develop the disorder may be partly inherited. Environmental factors may also play a role in their development, including stress, drug abuse, and major life changes.

In addition, people with certain psychotic disorders like schizophrenia may have abnormalities in the functioning of pathways in the brain that control thinking, perception, and motivation.  In schizophrenia, it is thought that nerve cell receptors that interact with a brain chemical called glutamate may not work properly in specific brain regions, and that this in turn may contribute to symptoms of abnormal thinking and perception. 

How Common Are Psychotic Disorders?

About 1% of the population worldwide suffers from psychotic disorders. These disorders most often first appear when a person is in his or her late teens, 20s, or 30s. They tend to affect men and women about equally.

How Are Psychotic Disorders Diagnosed?

If symptoms of a psychotic disorder are present, the doctor will perform a complete medical history and physical exam to determine the cause of the symptoms. Although there are no laboratory tests to specifically diagnose psychotic disorders -- except those that accompany a physical illness, such as a brain tumor -- the doctor may use various tests, such as blood tests and brain imaging (e.g., MRI scans), to rule out physical illness or intoxication with drugs like cocaine or LSD as the cause of the symptoms.

If the doctor finds no physical reason for the symptoms, he or she may refer the person to a psychiatrist or psychologist, mental health professionals who are trained to diagnose and treat mental illnesses. Psychiatrists use specially designed interview and assessment tools to evaluate a person for a psychotic disorder.

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