Objectives: Links between endorphins and dopaminergic transmission have not been fully explored in schizophrenia. Both endorphins excess and deficiency were postulated. CGRP is probably involved in dopaminergic transmission. The aim of this study was the evaluation of beta-endorphin (BE) and CGRP blood concentrations before and after treatment of severe schizophrenia.
Methods: Seventy patients treated with various antipsychotics, with severe symptoms of schizophrenia (51 with positive symptoms, 19 with negative symptoms), 15 first-degree relatives, and 44 healthy controls were included in the study. BE and CGRP blood concentrations were measured during patients severe schizophrenia and in their stable mental state after treatment. The results were compared with relatives and controls.
Results: BE and CGRP concentrations in patients with negative symptoms were higher than in relatives and in controls. BE levels in patients with positive symptoms were lower than in patients with negative symptoms (P<0.0000) and controls (P<0.0006). No significant changes in CGRP concentration were found in patient samples. CGRP levels in these samples were independent of treatment, but they were significantly higher than in relatives and controls. After the treatment, BE level decreased in patients with negative symptoms (P<0.0001) and increased in patients with positive symptoms (P<0.0000). No differences in BE concentration between patients in stable mental state, their relatives, and controls were found.
Conclusion: Effective antipsychotic treatment results in "normalization" of BE level. Specific changes in BE concentration could be involved in dopaminergic transmission and related to some symptoms of schizophrenia.
Keywords: CGRP; negative symptoms; neuroleptics; schizophrenia; β-endorphin.