Schizophrenia is a chronic mental disorder characterized by psychotic symptoms, which may include hallucinations, delusions, and disorganized thinking. People with schizophrenia have one or a combination of these symptoms, either episodically or persistently. All of the medications currently approved for the treatment of schizophrenia are considered antipsychotics, so they should be able to reduce or eliminate these experiences.

One way of thinking about the symptoms of schizophrenia is to consider them as either positive or negative. Positive symptoms are those that are new to the person after developing the illness. Psychotic symptoms certainly fall into this positive symptom category. Negative symptoms are things that are lost due to the illness.

The negative symptoms of schizophrenia are not as dramatic and obvious as the psychotic experiences, but they can have a large human cost by increasing the disability caused by the illness. However, the negative symptoms tend not to be so apparent because they often evolve gradually and so draw less attention to themselves than do the positive ones.
 
The loss of functioning that may accompany schizophrenia often has been outlined with a series of "a" descriptions, such as affective blunting, alogia, asociality, anhedonia, and avolition. These refer, respectively, to decreases in emotional expression, communication, socialization, ability to experience pleasure, and motivation. Early descriptions of schizophrenia also included ambivalence and autism as key characteristics.

Even when schizophrenic patients do not experience hallucinations, delusions, and disorganized thinking, their functioning may still be profoundly impaired due to the persistent negative symptoms. These may greatly limit education, employment, social and family relationships, self-care, and participation in treatment. Homelessness is the result for some people with schizophrenia.

Although the causes of schizophrenia are not fully understood, some evidence does suggest that the negative symptoms may be due to a neurodegenerative process, in which nerve cells are lost or degraded so that their ability to conduct messages is impaired. It remains to be seen whether medications ultimately will be able to slow or reverse this decline in functioning. The older antipsychotic medications were most effective for treating the positive symptoms, but the newer "atypical" antipsychotics may also be beneficial for the negative symptoms. There is hope that new medications will be developed to augment the treatment of schizophrenia by specifically targeting the pathological processes leading to these pervasive and disabling negative symptoms.