Guilherme Messas, MD (Psychiatrist), MSc, PhD, is currently Head of the Postgraduate Program on Phenomenological Psychopathology of the Santa Casa de São Paulo School of Medical Science; Lead for Brazil of the Collaborating Centre for Values-Based Practice in Health and Social Care, St Catherine's College, Oxford; Founding member and former president of the Brazilian Society for Phenomeno-Structural Psychopathology (SBPFE); Member of the World Psychiatric Association, Section of Philosophy and Humanities in Psychiatry. He is founding member and former editor in chief of the journal Psicopatologia Fenomenológica Contemporânea and has published many books and peer-reviewed articles in Portuguese, English and Italian, especially in Psychopathology of drug abuse. His main fields of interest are: Psychiatry, Substance misuse, Phenomenological Psychopathology, Phenomenological Psychiatry.