https://www.ed.ac.uk/profile/sergio-della-sala 
Psychiatric disorders (PDs), such as schizophrenia (SCZ), bipolar disorder (BD), and major depression disorder (MDD) are characterized by disturbances in the functioning of the CNS. These mental disorders have attracted the attention of researchers from different areas due to their high prevalence and extremely debilitating clinical characteristics. In spite of the many similarities observed among the PDs, not only in symptoms but also in the etiology as well, there is still a lack of knowledge in the biochemical and/or molecular pathways underlying each of these pathologies, in which better understanding could potentially help improve the diagnosis and possibilities for treatment. Several groups, including ours, have demonstrated that neuropeptidases and neuropeptidergic systems could play a fundamental role for the susceptibility of PDs such as SCZ, due to their involvement in the neurodevelopmental process (and consequent brain formation) and their recent association to disease progression. In this chapter, we bring an update of the main findings on neuropeptidases, such as Nuclear distribution element like-1 (NDEL1), angiotensin I-converting enzyme (ACE), and prolyl oligopeptidase (POP), with a detailed discussion on how they could be involved in the etiology of PDs. The main findings in the literature regarding alterations in neuropeptidase activity in different biological samples of patients with PDs, as well as in animal models, are presented here in order to draw the attention of general readers to the possibility of targeting this system for the discovery of new targets and/or development of novel therapies and gaining a deeper understanding of the molecular mechanisms underlying complex diseases such as PDs.
From Nani, J.V., Almeida, P.G.C., Hayashi, M.A.F., 2021. Neuropeptidases in Psychiatric Disorders. In: Della Sala, S. (Ed.), Encyclopedia of Behavioral Neuroscience, vol. 1. Elsevier, pp. 283–292. https://dx.doi.org/10.1016/B978-0-12-819641-0.00091-8. ISBN: 9780128196410 Copyright © 2021 Elsevier Ltd. All rights reserved Elsevier