The study will be conducted in a Regional Medium-Stay Unit (URME) belonging to the Murcia Health Service and located in the Román Alberca Hospital complex in El Palmar (Murcia), Spain. It is a care service for people with Severe Mental Disorder who, due to circumstances derived from their mental state or arising within their social context, experience difficulties maintaining their integration in the community or receiving care in an outpatient setting, thus requiring a period of medium- or long-term hospitalization.

A combined music therapy intervention (active and receptive) will be conducted in a group format. In each session, participants will select the songs they wish to listen to in relation to the topic being addressed. The songs will then be played, followed by a dialogue between the users and the professionals.

The intervention will consist of 15 sessions held weekly (over 15 weeks), each lasting approximately one hour.

This self-administered questionnaire assesses two aspects related to anxiety: state anxiety and trait anxiety. It consists of 20 items for each subscale (state anxiety and trait anxiety), with 4 response options ranging from 0 (Not at all) to 3 (Very much). Higher scores indicate a greater level of anxiety. The Spanish validated version shows a Cronbach's alpha of 0.9 for trait anxiety and 0.94 for state anxiety.

This self-administered questionnaire assesses the level of perceived stress. It consists of 14 items with 5 response options ranging from 0 (Never) to 4 (Very often). Higher scores indicate a higher level of perceived stress. The validated Spanish version shows a Cronbach's alpha of 0.81

This self-administered questionnaire assesses changes in the different dimensions of the recovery process. It consists of 15 items, each rated on a Likert scale from 0 (Strongly disagree) to 4 (Strongly agree). Higher scores indicate a greater level of recovery.

The validated Spanish version of this scale shows a McDonald's Omega coefficient of 0.93 and a Cronbach's alpha coefficient of 0.92

Participants will complete a self-developed satisfaction survey to assess their level of satisfaction with the intervention. Satisfaction will be measured using a 5-point Likert scale ranging from 1 (very dissatisfied) to 5 (very satisfied).