Eight patients with agoraphobia and panic attacks as defined by DSMIII and 11 controls were included in this study which measured the circulating biogenic amine levels. The method of assay used a high performance liquid chromatograph with electrochemical detection. Measurement of dopamine, noradrenaline and adrenaline showed no differences between the groups. Levels of serotonin (5-HT) were significantly lower in the agoraphobic group. The authors discuss the implication of this finding.