Psychotic disorders are severe mental disorders as defined by the current edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). The first chapter of this book reviews the most recent advances and research findings on the spectrum of negative symptoms across schizophrenia and affective psychosis. The second chapter is a review of literature that contributes to the rationale, development and evaluation of a program for a group approach, as considered according to the propriety of PoC (Propriety of Proof of Concept) for the treatment of schizophrenia. Chapter Three focuses on psychotic disorders and contributing factors in adolescence. In the fourth and final chapter of this book, the authors examine narcissistic wounds in music therapists, as well as the appropriate mechanisms to prevent them from appearing, such as personal therapy and supervision of the music therapist.