Psychologists and psychiatrists consider Schizophrenia to be at one end of a spectrum of related disorders that have psychosis (a break with reality) as a prominent feature. This group of disorders is called the Schizophrenia Spectrum and is described in this section.
Schizophrenia is not “split personality” as often misconceived. It is a condition in which characteristic symptoms have been present for a month or longer, with signs of the disorder present for at least six months. Characteristic symptoms include “positive” and “negative” symptoms. Positive symptoms are symptoms that are there which create problems. Examples of positive symptoms include highly disorganized speech or behavior, delusions (false beliefs), hallucinations (false sensory experiences including hearing and seeing things, tasting and smelling things, or sensations on or in the body that are not real). Auditory hallucinations, such as hearing voices talking to the person, are by far the most common type of hallucination in schizophrenia.
Negative symptoms are symptoms of abilities that are lacking in the patient that would be desirable to have. Examples include a flat or narrow range of emotional expression (flat affect), difficult initiating or sustaining speech (alogia), or a lack of ability to plan, organize, and carry out plans or activities of daily living.
In addition to the presence of positive and negative symptoms, to make the diagnosis the patient must show significant deterioration in social, academic, or occupational functioning. Self-care such as bathing, dressing, and personal hygiene often deteriorate over time as well. While the diagnostic criteria require only six months of continuous impairment, schizophrenia is usually a chronic disorder that can span years or decades. Subtypes of Schizophrenia include Paranoid, Disorganized, and Catatonic.
Schizophreniform Disorder is a milder disorder that involves the presence of positive and negative symptoms for at least a month, but the duration of the entire illness, including deterioration and recovery, lasts less than six months.
Schizoaffective Disorder is a disorder in which the patient displays an uninterrupted period of illness within which there also is a Major Depressive Episode or a Manic Episode. Such mood symptoms are prominent over the duration of the illness. In addition, the patient must also exhibit delusions or hallucinations for at least two weeks in the absence of prominent mood symptoms. Schizoaffective Disorder is often thought of as a blend of schizophrenic symptoms and manic or depressive symptoms.
Delusional Disorder involves delusions involving real life scenarios in which the patient feels that they are being harmed in some way, having a disease or infection, deceived by a partner, or loving or being loved at a distance. The patient does not meet criteria for Schizophrenia and functioning is within the normal range in that the patient shows no obvious impairment in functioning or behavior. Mood symptoms such as depression and mania are brief relative to the duration of delusions.
Brief Psychotic Disorder is a disorder in which the patient briefly exhibits positive symptoms lasting one day or longer but less than a month, with eventual return to normal functioning.
Shared Psychotic Disorder, also known as Folie à Deux, involves two (or more) people in close relationships. To make the diagnosis there must be the emergence and maintenance of a delusion in an individual which is shared with another individual who has a Psychotic Disorder with prominent delusions. The two individuals share the same delusional content, such as being followed or poisoned, in order to make this diagnosis.
Psychotic Disorder Not Otherwise Specified (NOS) is diagnosed when the patient has symptoms of a Psychotic Disorder but does not meet the criteria for any specific Psychotic Disorder diagnosis.