First generation antipsychotics seem to cause general brain volume loss, while second generation antipsychotics seem to both increase and decrease the thickness of different parts of the brain, according to a study led by University of Melbourne researchers published in Psychological Medicine. And the effects on the brain, they found, are noticeable within a matter of months of beginning to take the medications.

Participants in the research were drawn from a cohort of 162 first-episode patients diagnosed with schizophrenia or affective psychosis who’d been taking antipsychotics for about three months, and 87 controls, who were involved in the Early Psychosis Prevention and Intervention Centre study between 1994 and 1999.

The researchers found that the participants’ diagnosis or type of illness did not have any predictive effects on the amount or kind of brain volume changes. These findings were in line with other studies; however, unlike other studies, the researchers found differences between how the first-generation (FGAs) and second-generation antipsychotics (SGAs) were changing the brain.

“Analysis of each treatment group compared with controls demonstrated that FGAs were associated with decreased thickness in frontal regions, whereas SGAs were associated with increased thickness of pre- and postcentral gyri in addition to decreased thickness of medial frontal, parietal and fusiform areas,” the researchers stated.

“Our results suggest that FGA and SGA treatments have divergent effects on cortical thickness during the first episode of psychosis that are independent from changes due to illness,” they concluded. The researchers then suggested that the elements of brain thickening caused by second generation antipsychotics “may have positive benefits on symptoms.”

(Abstract) (Full text) Divergent effects of first-generation and second-generation antipsychotics on cortical thickness in first-episode psychosis (Ansell, B. et al. Psychological Medicine. February 2015. DOI: http://dx.doi.org/10.1017/S0033291714001652)