P-55 * TRYPTOPHAN ACUTE DEPLECTION TEST IN COCAINE DEPRESSED PATIENTS

Abstract

Introduction. Major depression is a common comorbidity in cocaine dependent (CD) subjects. A major challenge is to know if the comorbid depression episode is primary (PMD) or induced by the substance. Serotonergic system is implicated in both pathologies. Acute tryptophan depletion (ATD) has been used to evaluate serotonin function. The aim of the study is to observe differences in ATD response between PMD and cocaine-induced major depression (C-IMD). Methods. 23 CD patients (DSM-IV-TR) (14 with PMD and 9 with C-IMD) and 21 healthy controls have been assessed by ATD in a randomized double-blind crossover study. Mood changes during ATD by the Hamilton Rating Scale for Depression (HRSD) and tryptophan (TRP) plasma levels were evaluated at baseline (T0) and at 5hs (T5). Results. Those subjects with PMD showed changes in HRSD total scores in T5 (T0 mean = 1,57 ± 1,55 vs. T5 mean= 3,07 ± 2,058; p = 0.001), but not in C-IMD group (T0 mean =0,2 ± 0,6 and T5 mean = 0,5 ± 0,88) and in control group (T0 mean = 0,42 ± 0,76 and T5 mean =0,73 ± 1,1). In TRP plasma levels decreased in TDA-session and in Control-session behave as expected [1] but there were no differences between the controls and CD group. Conclusions. These results show a different response to ATD test between PMD and C-IMD in HRSD scores. These data support differences in the serotonergic system.