Positive symptoms are additional experiences that add to an individuals ordinary experience, while negative symptoms are the loss of a usual ability from everyday life. Positive symptoms include hallucinations and delusions. A hallucination is a sensory experience that commonly has no existence in reality, or can involve a distortion of things we perceive. For example, an individual with schizophrenia may report hearing voices or seeing people that are not there. Delusions in schizophrenia are irrational beliefs or paranoia. Often an individual experiencing delusions may report that they are someone else, that they have superpowers, or that they're a victim in a conspiracy. This results in a change in behaviour often seen as bizarre to the general population.
Negative symptoms that detract from usual abilities can be avolition or speech poverty. Avolition is a general loss of motivation to maintain activity towards a goal which results in reduced activity levels. Three signs of avolition are poor hygiene, lack of energy and lack of persistence in work/education (Andreason ,1982). Speech poverty is a second negative symptom of schizophrenia which reduces the quality and quantity of speech produced by the individual. This can often be seen during conversations with the patient as their responses are delayed.