Altered Brain Chemistry in Schizophrenia
Every drug now available to treat psychotic symptoms targets a subtype of dopamine neurotransmitter receptor called the D2 receptor. The correlation between a drug's interactions with D2 receptors and its ability to ease psychotic symptoms at low doses is greatest for the older antipsychotic medications. Newer drugs probably owe many of their good and bad effects to their tendency to bind more strongly to serotonin and other types of receptors instead of the D2 receptor.
Symptoms and Receptors
Schizophrenia symptoms fall into two main classes, positive and negative. Some research suggests that positive symptoms might be traced to changes predominantly centered in one part of the brain and negative symptoms to another part.
Some clinical observations support this scheme: antipsychotic drugs that predominantly block a subset of dopamine receptors in the basal ganglia are better at controlling positive symptoms. Medications that seem to be better at controlling negative symptoms block different chemical messengers in the brain and may exert their anti-schizophrenia effects in the prefrontal cortex.