From Nature:
Evidence that prescription drugs shrink patients' brains would, one might think, suggest only one course of action: stop prescribing them. But the matter turns out to be much more complicated, according to research published today in Archives of General Psychiatry on the effects of antipsychotic drugs in people with schizophrenia1.
In the past 15 years, research has indicated that people with schizophrenia have smaller cerebral volumes than the general population, and that this reduction is particularly large in 'grey-matter' structures, which contain the cell bodies of neurons. For instance, one meta-analysis points to 5–7% reductions in the size of the amygdala, hippocampus and parahippocampus2, which are all involved in memory storage and retrieval. But scientists have debated whether the decrease is caused by the disease alone, or whether powerful antipsychotic drugs also have a role. According to the latest findings, the more antipsychotics patients receive, the more likely they are to have a decreased amount of grey matter.
More here.