The DSM-IV diagnosis of schizophrenia describes a range of psychotic symptoms. Psychosis refers to a significant break with reality testing, or the ability to recognize reality as other people who are in similar circumstances typically see it. There are a number of different types of psychotic symptoms:

• Delusions refer to a fixed, false belief that is considered abnormal within the person’s culture.
• Bizarre delusions are physically impossible, as in the belief that the queen of England is on the planet Mars sending messages to a chip in your brain. A non-bizarre delusion is physically possible, such as the false belief that a celebrity is in love with you or that you are being bugged by the FBI.
• Hallucinations refer to a perceptual experience of something that is not really there. Hallucinations can be auditory (sense of sound), visual (sense of sight), olfactory (sense of smell), or tactile (sense of touch). Auditory hallucinations are the most common, and often involve one or more voices talking.
• Disorganized speech and behavior generally reflect disorganized thought, a breakdown of the coherent, logical flow of thought.

All the symptoms mentioned so far refer to positive symptoms or problematic traits that are present. In contrast, negative symptoms reflect the absence of healthy traits. Specifically, negative symptoms refer to blunted or flat affect (or emotion) and a dulling of motivation, initiative, energy, and cognitive activity.