Although schizophrenics may view their abnormal perceptions and paranoid beliefs as perfectly rational, their behavior often appears out-of-pace and bizarre to others.

Symptoms of Schizophrenia

Schizophrenic symptoms typically begin between adolescence and early adulthood; onset often corresponding to a stressful or transitional period, such as going off to college or beginning full-time employment. Initial symptoms may include delusions and hallucinations, and disorganized behavior or speech. Over time, as the disorder progresses, additional symptoms may develop, such as a reduced range of emotional expression (Butcher 2007).

Hallucinations & Delusions

There are several subtypes of schizophrenia and symptoms are extremely variable, but frequently include aural, visual, or other sensory hallucinations, such as hearing disembodied voices or seeing and feeling things that aren’t actually present. Delusions, or false believe that are in conflict with reality, are also commonly experienced.

Schizophrenics may believe that others are controlling their thoughts, or have an unfounded suspicion that people are plotting to harm them. These experiences are frightening and can result in the withdrawal and extreme agitation often associated with schizophrenia.

Positive and Negative Symptoms

Symptoms of schizophrenia are typically categorized as being either “positive” or “negative.” Positive refers to the presence an excess or distortion of normal experience, such as hallucinations, delusions, racing thoughts; whereas negative refers to a reduction or absence of normal emotion or behavior, such as apathy, lack of emotion, or poor social functioning. There are also symptoms that are considered cognitive as relating to thought processes, such as disorganized thoughts, memory problems or difficulty concentrating, following instructions, and completing tasks (Butcher 2007).

The Schizophrenic Continuum

Schizophrenia is considered by some to be part of the "schizophrenic spectrum" of mental illness, which also includes Schizotypal Personality Disorder and Schizoid PD. Although Schizophrenia is categorized as a Psychotic Disorder and both Schizoid and Schyzotypal are Personality Disorders, all three share symptoms, such as avoidance of social relations and flat emotional affect. An important difference is that people with schizoid personality don't typically experience the perceptual distortions, paranoia or illusions typical of Schizotypal Personality or the psychotic episodes of Schizophrenia (Questa 2001, Widiger 2007).

Diagnosis of Schizophrenia

At the present time, there are no physical or laboratory tests that can absolutely confirm or rule out a diagnosis of schizophrenia. Typically diagnosis is made by a psychiatrist and is based on clinical symptoms.

A summary some characteristic symptoms, based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) includes:

• Delusions
• Hallucinations
• Disorganized speech (frequent derailment or incoherence)
• Grossly disorganized or catatonic behavior
• Negative symptoms

1. flat affect (reduced range of emotional expression)
2. alogia (reduced speech fluency or productivity)
3. avolition (absence of goal directed behavior)

• Cognitive symptoms (difficulties with concentration and memory).

The above list is only a portion of the lengthy criteria used by professional in diagnosing schizophrenia. The complete diagnostic criteria is complex and includes numerous and lengthy descriptions of the conditions that must be met for diagnosis.

Misdiagnosis of Schizophrenia

Since there is no simple, objective test to confirm presence of the disorder, and because schizophrenia shares many symptoms with other disorders, misdiagnosis is a continuing issue and obstacle to appropriate treatment. According to a year 2000 survey of National Depression and Bipolar Support Alliance members, 1/3 of psychiatric patients wait 10 years for a correct diagnosis. Being aware of the potential for misdiagnosis and recognizing other disorders that have a similar presentation can help the patient to more quickly receive a correct diagnosis and appropriate treatment.

More Information on Psychological Disorders

There are numerous on-line and in print resources with additional information on psychiatric disorders, including: Psychology Prof Online and Schizphrenia.com.

This article is a brief summary of schizophrenia symptoms and diagnostic criteria. The contents of this article are not meant to be used for diagnosis and are not a substitute for professional help and counseling.

Additional Sources

American Psychiatric Association APA (2000) Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR).

Butcher, J. N., Mineka, S. and Hooley, J. M. (2007) Abnormal Psychology. Pearson/Allyn & Bacon.

Questa, M. J., Peralta, V., and Zarzuela, A. (2001) Are personality traits associated with cognitive disturbance in psychosis? Schizophrenia Research, 51, 2-3.

Widiger, T. A. (2007) Dimensional Models of Personality Disorders

Refining the Research Agenda for DSM-V. American Psychiatric Publishing, Inc.