A diagnosis of schizophrenia can be made when two or more prominent symptoms consistent with the illness (e.g., delusions, hallucinations, disorganized speech or behavior, negative symptoms) are present for the better part of a month or more, and substantial social or occupational functioning problems are noted to exist. If the diagnosis of schizophrenia is made, a subtype of the illness must be specified as well. There are five recognized subtypes of schizophrenia: paranoid, disorganized, catatonic, undifferentiated, and residual:
Paranoid schizophrenia is characterized by prominent delusions and (usually auditory) hallucinations that wax and wane across recurrent psychotic episodes. Multiple delusions may be present but generally all will share a coherent theme (e.g., delusions may be persecutory or grandiose, or religious in nature, etc.) There may be command hallucinations that drive patients to complete odd or bizarre goals. Affected individuals tend to be anxious, frightened, angry, aloof, and argumentative; they may have a superior and patronizing manner and formal or extremely intense interpersonal interactions. The combination of delusions and anger can lead to violence towards self and/or others, although this is not a common occurrence (See Stigma and Violence, above). Individuals newly diagnosed with paranoid schizophrenia tend to show little to no impairment on brain scans and psychologically tests. Provided they receive prompt proper medical treatment, their prognosis can be good. Some substantial number of individuals with paranoid schizophrenia are able to work (although not in high-stress occupations) and retain the capacity for independent living.
Catatonic schizophrenia patients demonstrate disturbed movement, somatic (body) and language symptoms. They sometimes strike odd (and probably uncomfortable) poses, and then hold those poses for hours. They may be mute during these episodes, refusing to speak, and/or make odd facial expressions. They may resist attempts to change their positions. At other times they may move about quite freely, demonstrating seemingly purposeless and undirected motor activity, or imitating other people's movements. When not mute, they may speak by echoing phrases that others have spoken to them. Whether out of neglect or excitement, patients may end up harming themselves (e.g., through malnutrition, exhaustion, hyperpyrexia, or self-inflicted injury).
This classification is used when patients display definite positive and negative symptoms of schizophrenia, but none of their symptoms dominates their presentation, allowing their classification into either paranoid, disorganized, or catatonic categories.
This type of schizophrenia is diagnosed in patients who have had prior psychotic episodes (one or more) warranting the diagnosis of schizophrenia, but who also do not currently display strong positive symptoms (e.g., hallucinations, delusions). Mild disorganized speech, eccentric behavior, flat affect, or poverty of speech may be present, however. The residual state may be sustained for years, or patients may end up with new episodes of psychosis.
The following diagnostic criteria must be met before a diagnosis of Schizophrenia is warranted, according to the DSM-IV-TR:
A) Characteristic Symptoms: Two (or more) of the following, each present for a significant portion of time during a 1-month period (or less if successfully treated)
3. disorganized speech (e.g., frequent derailment or incoherence)
4. grossly disorganized or catatonic behavior
5. negative symptoms, i.e., affective flattening, alogia, or avolition
B) Social/occupational dysfunction: For a significant portion of the time since the onset of the disturbance, one or more major areas of functioning such as work, interpersonal relations, or self-care are markedly below the level achieved prior to the onset (or when the onset is in childhood or adolescence, failure to achieve expected level of interpersonal, academic or occupational achievement).
C) Duration: Continuous signs of the disturbance persist for at least 6 months. This 6-month period must include at least 1 month of symptoms (or less if successfully treated) that meet Criterion A (i.e., active-phase symptoms) and may include periods of prodromal or residual symptoms. During these prodromal or residual periods, the signs of the disturbance may be manifested by only negative symptoms or two or more symptoms listed in Criterion A present in an attenuated form (e.g.,odd beliefs, unusual perceptual experiences).
D) Schizoaffective and Mood Disorder exclusion: Schizoaffective Disorder and Mood Disorder With Psychotic Features have been ruled out because either 1) no Major Depressive, Manic or Mixed Episodes have occurred concurrently with the active-phase symptoms; or 2) if mood episodes have occurred during active-phase symptoms, their total duration has been brief relative to the duration of the active and residual periods.
E) Substance/general medical condition exclusion: The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.
F) Relationship to a Pervasive Developmental Disorder: If there is a history of Autistic Disorder or another Pervasive Developmental Disorder, the additional diagnosis of Schizophrenia is made only if prominent delusions or hallucinations are also present for at least a month (or less if successfully treated).