The Evolution of the Iso Principle in Music Therapy and Music Listening


The term “iso principle” is unique to the field of music therapy. It was first introduced in the late 1940’s by Altshuler as a method of mood management in which the music therapist provides music that matches their client’s mood, then gradually changes the music to help the client shift to a different mood.

While Altshuler’ original “iso principle” method involved a system of programmed classical music, the term has a much broader scope now. In its most basic sense, the iso principle means meeting your clients wherever they are at that current moment. If a music therapist is working with a hospice patient who is in a depressive state, it would be inappropriate, ineffective, and potentially harmful to start the session with a loud, fast, upbeat song. According to the iso principle, the music therapist should begin with some slow, quiet, and contemplative music, and gradually work up to something more upbeat and joyful through the course of the session.

Despite the fact that the iso principle is commonly known and used throughout the field of music therapy, there has been little research done on the use of the iso principle. Dr. Annie Heirderscheit and Amy Madson, both board-certified music therapists, conducted a case study that used the iso principle in a manner similar to Altshuler’s original intentions. They created a therapeutic playlist for their client, a 57 year old woman with co-morbid diagnoses of Eating Disorder Not Otherwise Specified, Major Depressive Disorder, and Generalized Anxiety Disorder. The playlist consisted of Celtic music from the client’s own collection, and was created by a collaborative effort by the music therapists and the client. The client identified songs that she felt expressed both her depressive moods and her hopeful moods, which served as opposite ends of the continuum. The music therapists then created a rating system by which they ranked other music from the client’s collection and then created a playlist. The order of the songs was intended to help connect to the client’s mood and help her shift to a more hopeful, optimistic mood.

The client had great success with her playlist and reported that she was using it in multiple settings. She said she loved how she could start the playlist at any point to match her current mood. The playlist continued to serve as a coping tool for the client as she switched medications, and helped her feel empowered, as she now had a tool she could use on her own to help manage her mood.

While not all therapeutic settings call for a personalized playlist, this article helps us understand the history and the continued use of the iso principle and provides implications for using the iso principle in music therapy practice as well as role in individualized music listening programs such as Music & Memory.

Heiderscheit, A. & Madson, A. (2015) Use of the iso principle as a central method in mood management: A music psychotherapy clinical case study. Music Therapy Perspectives 33(1), 45-52

Alyssa Graber, MME, MT-BC