Schizophrenia is a chronic, severe, and disabling brain disorder affecting approximately 1% of Americans.[Regier 1993] The symptoms of schizophrenia fall into 3 broad categories: positive, negative, and cognitive.[NIMH Schizophrenia booklet, 2009]

Positive symptoms

Positive symptoms are psychotic behaviors not observed in persons without schizophrenia. These symptoms can wax and wane, being at times severe and at other times hardly noticeable; this can depend on whether the individual is receiving treatment:

  • Hallucinations, most commonly, voices that other people cannot hear
  • Delusions, ie, false beliefs that are not part of the person’s culture and that do not change
  • Thought disorders, such as disorganized thinking, in which an individual has trouble organizing thoughts or connecting them logically
  • Movement disorders, such as agitated body movements or certain repeated movements

Negative symptoms

Negative symptoms are more difficult to recognize and can be mistaken for depression or other conditions. People with negative symptoms need help with everyday tasks, often neglecting such things as personal hygiene. Negative symptoms may include:

  • Flat affect, in which a person’s face does not move or he or she talks in a dull, monotonous voice
  • Lack of pleasure in daily activities
  • Lack of ability to begin and sustain planned activities
  • Speaking little, even when required to interact

Cognitive symptoms

Cognitive symptoms are subtle, may be difficult to recognize as part of schizophrenia, and often are detected only when special tests are performed. Cognitive symptoms may include:

  • Poor executive functioning, ie, the ability to understand information and use it to make decisions
  • Trouble focusing or paying attention
  • Problems with working memory, ie, the ability to use information immediately after learning it


Schizophrenia occurs in men and women equally and at similar rates in all ethnic groups. Symptoms such as hallucinations and delusions usually start between 16 and 30 years of age. Men tend to experience symptoms a little earlier than women. People typically do not develop schizophrenia after age 45, and it rarely occurs in children. [Mueser 2004]

Some people who abuse drugs exhibit symptoms similar to those of schizophrenia, for that reason schizophrenic persons may mistakenly be considered to be under the influence of drugs. Although researchers do not believe that substance abuse causes schizophrenia, individuals with schizophrenia are much more likely to abuse alcohol or other substances than members of the general population. [Blanchard 2000]




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