Increased cerebrospinal fluid levels of endorphin immunoreactivity in panic disorder

Cerebrospinal fluid (CSF) concentrations of beta-endorphin-like immunoreactivity (END-IR) were determined in 11 female and 6 male patients fulfilling the diagnostic criteria of panic disorder (PD) and in matched controls. Eleven of the PD patients had been taking moderate doses of benzodiazepines (BZD) irregularly without satisfactory effect against the panic attacks while six were totally drug-free. No medication was allowed for at least 24 hours before the lumbar puncture. In six patients a second lumbar puncture was performed after 2 to 3 months of treatment with imipramine or clomipramine. In PD patients, CSF levels of END-IR were significantly higher than in controls. Patients that had been taking BZD had somewhat higher concentrations of END-IR than those taking no medication; however, totally drug-free patients also displayed END-IR levels that were significantly higher than in controls. Although they effected a dramatic reduction of the panic attacks, antidepressants did not influence CSF END-IR concentrations.