Participants shall engage in the standard activities required at the compulsory isolation drug rehabilitation centre, whilst researchers will supplement the subjects' regimen with an exercise therapy programme.

Participate in the standard activities required at the compulsory isolation drug rehabilitation centre, whilst researchers will supplement the treatment regimen for subjects with exercise combined with fast-paced music.

Participants will engage in standard activities required at the compulsory isolation drug rehabilitation centre, whilst researchers will supplement the treatment regimen with exercise combined with slow-tempo music.

The intervention groups in the experiment comprised three main categories: an exercise-only group, an exercise-combined-with-fast-paced-music group, and an exercise-combined-with-slow-music group. Participants engaged in activities mandated by the compulsory isolation drug rehabilitation centre, while researchers administered three distinct treatment protocols to the subjects.

Depression serves as the single core indicator under investigation, assessed via two independent scales: ① the Common Depression Questionnaire (CBD), and ② the Quick Inventory of Depressive Symptoms (QIDS-SR16).

Both scales measure participants' depressive states, yet results will be presented and analysed separately to enhance the reliability and stability of depression symptom assessment.

The CBD scores range from 0 to 63 points, with higher scores indicating greater severity of depression. Scores are categorised as follows: no depression (0 to 19); mild depression (20 to 29); moderate depression (30 to 39); and severe depression (40 or more).

The QIDS-SR16 ranges from 0-27 points, with higher scores indicating greater depression severity.1-5 points: no depression; 6-10 points: mild depression;11-15 points: moderate depression; 16-20 points: severe depression; 21-27 points: very severe depression.

This study employed the Mannheim Craving Scale (MaCS) German version and the Visual Analogue Scale (VAS) to assess participants' drug craving levels. Both instruments measure the same core indicator, "drug craving level", but were recorded and analysed as independent measurement tools to enhance measurement reliability and reflect the breadth of the dimension.

• MaCS (German version) is a graded rating scale (scoring range: 0-48 points, with higher scores indicating stronger craving)
• VAS visual analogue scoring employs a 0-10 cm quantitative scale, where 0 denotes complete absence of craving and 10 denotes extremely strong craving

Measurement timepoints: One baseline measurement prior to the experiment, followed by monthly measurements during the experiment, totalling seven measurements over six months.