Background Negative symptoms hamper treatment progress of patients with schizophrenia. Aim This study evaluates the effect of a music therapy module on negative symptoms, composed of activating music therapy as usual, augmented by elements of neurologic music therapy on negative symptoms. Method A pre- and posttreatment measurement with the Dutch version of the Brief Negative Symptom Scale has been taken from five forensic psychiatric patients and their personal nurses. During the module, sociotherapist scored the Negative Symptom Scale three times a week. Applying the reliable change index and simulation modeling analysis, the quantitative change in negative symptoms was analyzed for each patient, supported by a qualitative analysis of the medical files. Results Four out of five patients showed reduction in negative symptoms. Conclusion Music therapy seems to have a positive effect on the reduction of negative symptoms and regaining of activity and treatment motivation in forensic psychiatric patients, who prior to the study were long-lasting inactive and difficult to motivate. Adjusting the music therapy to individual needs, personalized treatment, is in line with the complexity of the target group.