EVALUATION OF BRAIN PERFUSION WITH TC-99M BICISATE SINGLE-PHOTON EMISSION TOMOGRAPHY IN PATIENTS WITH DEPRESSIVE DISORDER BEFORE AND AFTER DRUG-TREATMENT

Depression is one of the most common psychiatric illnesses. Its influe nce on brain perfusion has been demonstrated, but conflicting data exi st on followup after drug treatment. The aim of our study was to evalu ate the effects of antidepressant drugs on regional cerebral blood flo w (rCBF) in patients with depression after 3 weeks and 6 months of dru g therapy. Clinical criteria for depression without psychosis were met according to psychiatric evaluation. Severity of depression was evalu ated with the Hamilton Depression Rating Scale (HAMD) before every sci ntigraphic study, rCBF was assessed using technetium-99m bicisate (Neu rolite) brain single-photon emission tomography in nine patients with severe depression before the beginning of antidepressant drug therapy and 3 weeks and six months after initiation of therapy. Only patients with no change in antidepressant medication during the study were incl uded. No antipsychotic drugs were used. Cerebellum was used as the ref erence region, rCBF was evaluated for eight regions in each study in t hree consecutive transversal slices. Follow-up studies were compared w ith the baseline study. The mean HAMD score was 25.5 points initially, 16 at the second examination and 8.8 after 6 months. Global CBF was d ecreased compared with the reference region in drug-free patients, Per fusion of left frontal and temporal regions was significantly lower (P <0.005) in comparison with the contralateral side. After therapy, a mo derate decrease in perfusion was seen in the right frontal region (P<0 .05). Perfusion decreased further after 6 months in the right frontal (P<0.005) and temporal regions (P<0.01). The highly significant asymme try in perfusion between the left and right frontal and temporal lobes almost disappeared during treatment, Our findings implicate dysfuncti on of the frontal and temporal cortex in clinically depressed patients before specific drug treatment, Clinical improvement and decreases in HAMD score after 3 weeks and after 6 months reflect the treatment eff ect on mood-related rCBF changes.