Prefrontal cortical dendritic spine pathology in schizophrenia and bipolar disorder

Abstract

Importance

Prior studies have demonstrated reduced dendritic spine density in the dorsolateral prefrontal cortex (DLPFC) in schizophrenia. However, it remains unclear how generalizable this finding is in schizophrenia and if it is seen in a historically distinct psychiatric condition, bipolar disorder.

Objective

To assess whether spine loss is present in the DLPFC of subjects with schizophrenia and bipolar disorder.

Design, Setting, and Participants

This study utilized postmortem human brain tissue from subjects with schizophrenia (n=14), bipolar disorder (n=9) and unaffected control subjects (n=19). Tissue samples containing the DLPFC (BA 46) were Golgi-stained, and basilar dendrites of pyramidal cells in the deep half of layer III were reconstructed.

Main Outcomes and Measures

The number of spines per dendrite, spine density, and dendrite length were compared across groups. We also assessed for the potential effects of clinical and demographic variables on dendritic parameters.

Results

Spine density was significantly reduced in bipolar disorder subjects. In schizophrenia subjects, spine density was also reduced, but just missed significance. Relative to control subjects, there was a significant reduction in the number of spines per dendrite in both schizophrenia and bipolar disorder subjects. In addition, both schizophrenia and bipolar disorder subjects had reduced dendrite length.

Conclusions and Relevance

Dendritic spine loss in the DLPFC was seen in both schizophrenia and bipolar disorder subjects suggesting that the two disorders may share some common pathophysiological features.