Reduced anxiety level by therapeutic interventions and cell-mediated immunity in panic disorder patients

OBJECTIVE: This study examined the relationship between reduced anxiety level by therapeutic interventions and cell-mediated immunity (CMI) in patients with panic disorder. METHODS: The subjects consisted of 42 patients with panic disorder and 42 normal gender- and age-matched controls. Among the patients, 21 were randomly assigned to a combined treatment of cognitive-behavioral therapy and the benzodiazepine antianxiety agent ethyl loflazepate (2 mg daily), and 21 were assigned to the antianxiety agent only. The treatment lasted for 6 weeks. Cell-mediated immune function was measured by the lymphocyte proliferative response to phytohemagglutinin (PHA) and interleukin-2 (IL-2) production. The anxiety level was assessed by the Hamilton Rating Scale for Anxiety and the anxiety subscale of the Symptom Checklist-90 Revised. RESULTS: Prior to treatment, the panic disorder patients had significantly lower IL-2 production and blastogenic response to PHA than the normal controls. However, no significant differences in CMI were found between the pretreatment and posttreatment period in either the patient group receiving medication only or the combined treatment group, though after treatment, patients were significantly less anxious than before treatment in both intervention groups. The delta change (posttreatment value minus pretreatment value) in the self-reported anxiety level was significantly associated with the delta change in the blastogenic response in the combined treatment group. CONCLUSION: These findings suggest that panic disorder may be associated with decreased CMI, and the reduced level of self-reported anxiety in the patients who underwent combined therapeutic intervention is likely to increase the blastogenic response. Further studies are needed to evaluate the long-term effects of treatment on immune function.