Psychopharmacology is the study of drugs and how they affect behaviour. If you break down the word, it tells you exactly what it means.... "psycho" like psychology, or the study of behaviour, "pharm" is how the drug works in the body and brain, and bioology means to study. So pharmacology is the study of drugs, and psychopharmacology is the study of how these drugs will affect the behavioural processes of humans.
The main purpose of study in this area is to find drugs that will help alleviate the symptoms of psychological disorders like schizophrenia or depression. An important aspect of this research is that the drugs have a psychoactive effect based on how they work in the brain and it is the alteration of brain dysfunction that will help alleviate symptoms of disorders. An example might be Haldol (haloperidol) for schizophrenia which works on the dopamine system or Valium (diazepam) for anxiety which works on GABA receptors, although drugs are used to help with almost every disorder.
What kind of psychoactive affect would these drugs have on a brain that has such dysfunction? Are these drugs administered with therapeutic intervention as well, or would it just be given and monitored?