1. Association: thought disorder, as might be evident through rambling and incoherent speech
2. Affect: disorder of the experience and expression of emotion- for example, inappropriate laughter in a sad situation
3. Ambivalence: the inability to make or follow through on decisions
4. Autism: the tendency to maintain an idiosyncratic style of egocentric thought and behavior

• Delusions
• Hallucinations
• Disorganized speech
• Disturbed or catatonic behavior 
• Negative symptoms, such as flat affect or severe lack of motivation

Delusions, hallucinations, disorganized speech, disturbed behavior, and negative symptoms (i.e. speechlessness or lack of initiative)

A period prior to the active phase during which the individual shows progressive deterioration in social and interpersonal functioning. It is characterized by several maladaptive behaviors, such as social withdrawal, inability to work productively, eccentricity, poor grooming, inappropriate emotionality, peculiar thought and speech, unusual beliefs, odd perceptual experiences, and decreased energy and initiative.

There are continuing indications of disturbances similar to the behaviors of the prodromal phase. Due to the disturbances, people with schizophrenia experience serious problems in work, relationships, and self care during this phase.

Positive symptoms are exaggerations or distortions of normal thoughts, emotions, and behavior, and are viewed as direct lead-ins to the full expression of psychosis while negative symptoms involve functioning below the level of behavior regarded as normal.

A preoccupation with one or more bizarre delusions or have auditory hallucinations related to a theme of being persecuted or harassed, but without disorganized speech or disturbed behavior.

Individual shows a complex of schizophrenic symptoms, such as delusions, hallucinations, incoherence, and disturbed behavior, but does not meet the criteria for the paranoid, catatonic, or disorganized types of schizophrenia.

A disorder characterized by a sudden onset of psychotic symptoms which last less than 3 months

Disorder in which an individual has the same psychotic symptoms as those found in schizophrenia but the active symptoms last only 1-6 months while those with Schizophrenia have the symptoms for a longer duration.

One or more people develop a delusional system as a result of a close relationship with a psychotic person who is delusional and occurs in the context of a close relationship in which there is a history of pathological dependence. 

What have brain imaging methods found in the brains of people with schizophrenia?

Those with Schizophrenia have enlarged ventricles within the brain, often accompanied by cortical atrophy (a wasting away of brain tissue).

• Biological factors- differences exist in the brain structure and functioning of people with schizophrenia compared with those of others.
• Heredity- there is a strong likelihood that people with schizophrenia have relatives with this disorder and the closer the relative, the greater the rate of concordance.
• Environmental factors can trigger the disorder.