experimental group receiving the MT programme in addition to their usual treatment (pharmacological and psychosocial) (TAU + MT)

Group with usual treatment only (TAU).

The session-based intervention programme was designed with an integrated and multimodal perspective of music therapy [37], which allows the combination of active and passive activities together with focuses and perspectives based on empirical evidence [38]. It was implemented using a process-based approach, adapting content to different phases in the process: initial contact, managing resistance, confidence building, relationships, awareness, and closure. The central focus is on the patient and to adapt and remain flexible in the sessions in accordance with the capabilities and needs of the group members. Different perspectives are integrated via nonverbal communication. The layout and any changes to the setting are made in a gradual way in keeping with the process to foster feelings of security and belonging. Sessions begin with a brief period of breathing which then moves into warming-up and free-expression using instruments, followed by the central activity and the closure.

Symptoms of schizophrenia are measured according to the subscale scores and total score on the PANSS which consists of 30 items scored from 1 (Absent) to 7 (Extreme). Scores range from 30 to 210, with higher scores indicating more symptoms.

The State-Trait Anxiety Inventory (STAI) is a psychological inventory based on a 4-point Likert scale and consists of 40 questions on a self-report basis. The STAI measures two types of anxiety - state anxiety, or anxiety about an event, and trait anxiety, or anxiety level as a personal characteristic.Scores range from 20 to 80, with higher scores correlating with greater anxiety.

The WHOQOL-BREF contains 24 questions covering 4 domains plus two questions related to overall quality of life and satisfaction with health. Highes scores represent higher quality of life.