Panic disorder (PD) is a common and debilitating anxiety disorder. Recent neuroanatomical theories of PD propose an extensive involvement of limbic system in pathophysiology of this condition. In fact, several structural and functional neuroimaging studies have shown changes in limbic structures, such as hippocampus in PD patients. Despite this, no prior studies have examined hippocampal neurochemistry in this disorder. The current study used proton magnetic resonance spectroscopy imaging (1H-MRSI) to examine possible neurochemical abnormalities in hippocampus in PD patients.

Twenty-five patients meeting the DSM-IV criteria for PD and eighteen psychiatrically healthy controls were investigated. The subjects were paired based on gender, age, years of education, handedness, and socioeconomic level. N-acetylaspartate (NAA, a putative marker of neuronal viability) and choline (Cho, involved in the synthesis and degradation of cell membranes) levels were quantified relative to creatine (Cr, which is thought to be relatively stable among individuals and in most brain areas) in both right and left hippocampus.

Compared with controls, panic patients demonstrated significantly lower NAA/Cr in the left hippocampus. No other difference was detected.

This result is consistent with the previous findings of hippocampal alterations in PD and provides the first neurochemical suggesting of involvement of this structure in the disorder.