Adiponectin, resistin, interleukin-4 and TGF-β2 levels in treatment resistant schizophrenia patients

Background: The aim of the present study was to measure adiponectin, resistin, interleukin-4 and TGF-β levels in first episode, treatment resistant patients with schizophrenia.

Methods: In total, fifty-three treatment-resistant patients were included in the study. In subgroups of these patients, we measured Interleukin-4 (IL-4), Tumor Growth Factor-β2 (TGF-β2), adiponectin and resistin levels at three different timepoints: in the drug-naïve state, after two rounds of treatment with different antipsychotic drugs for a total of 16 weeks and, after clozapine treatment for 12 weeks.

Results: TGF-β2 and adiponectin levels decreased after treatment with olanzapine and risperidone, while resistin and IL-4 levels did not differ significantly.Comparing the levels of the aforementioned cytokines before the initiation and after clozapine treatment, we found an even greater decrease in adiponectin levels while resistin and IL-4 levels significantly increased and TGF-β2 levels did not differ significantly.

Conclusions: We report elevated resistin and IL-4 levels and decreased adiponectin levels in first-episode, treatment resistant schizophrenia patients after clozapine treatment. These findings may be at least partly due to the anti-inflammatory action of clozapine, although sub-clinical metabolic disturbances may also have played a role as far as resistin and adiponectin are concerned. In a subgroup of these patients we report reduced TGF-β2 and adiponectin levels after two unsuccessful trials with risperidone and olanzapine comparing them with the ones of the same subgroup in the drug-naïve phase.