On the Neural Mechanisms of Music Therapy in Mental Health Care: Literature Review and Clinical Implications

Abstract

IntroductionHow can music therapy contribute to emotional health from a neurobiological perspective? Music's role in mediating emotions has been investigated for decades by researchers in psychology, neuroscience, and music therapy, among other disciplines. However, many questions remain largely unanswered-particularly those related to the potential of music to promote healthy emotion regulation. This is especially relevant to music therapists in mental health settings.Psychology researchers have already provided models to help understand the connection between music and emotions. Juslin and Vastfjall (2008) describe seven ways in which musical stimuli can induce emotions. First, musical elements can trigger brainstem reflexes related to survival mechanisms. For instance, a fast tempo or a surprisingly loud sound might cause arousal. Second, music that is repeatedly paired with positive or negative stimuli can be classically conditioned to induce emotions. Third, features of music that mimic other emotional contexts can lead to a contagious effect; consider the slow, soft voice of a violin and emotions linked to slow, soft speech. Fourth, music can lead to new mental imagery. Fifth, music can also conjure episodic memories, or old mental imagery. Sixth, features of musical syntax can mediate emotions through musical expectancy, such as a chord progression without harmonic resolution. Finally, the presence of music can directly affect personal/therapeutic goals of any listener, such as the sound of sedative music helping someone fall asleep.Juslin and Vastfjall's (2008) model provides a psychological foundation for music-induced emotions. However, it does not account for emotional processes that uniquely affect active music-making or the interpersonal emotional possibilities of group/dyad music therapy. Nor does it explain (or attempt to explain) the connections between music-induced emotions and non-musical components of therapeutic practice, such as verbal processing and the client-therapist relationship.Similarly, the neurobiology literature is primarily focused on emotional mechanisms during music listening, although some investigators have also explored active music-making. Chanda and Levitin (2013) summarize evidence that demonstrates how music can influence neurochemistry in four ways. First, music listening has been shown to affect neurotransmission in the brain's reward pathways. Second, music can influence hormonal levels via the hypothalamic-pituitary axis. Listening to relaxing music, for instance, has been shown to decrease blood levels of cortisol-a marker for stress. There is also evidence for decreased cortisol following music therapy interventions, such as Guided Imagery and Music (Burns, 1999; McKinney, Antoni, Kumar, Tims, & McCabe, 1997). Third, Chanda and Levitin cite drum circle studies that have shown increased immunological measures among participants-such as increased natural killer T-cells and 5-DHA-to-cortisol ratio (Bittman et al., 2001). Fourth and finally, the authors describe evidence of music's impact on hormones related to social affiliation (to be addressed further herein). Although their literature review does not focus specifically on music-induced emotions or mental health treatment settings, the biological mechanisms they discuss have applications in both of these realms.Within the body of music therapy literature, researchers have repeatedly demonstrated that music-based interventions can affect emotional patterns in individuals receiving mental health treatment (Bensimon, Amir, & Wolf, 2008; Bloch, Reshef, Vadas, Haliba, & Ziv, 2010; Carr et al., 2012; Cevasco, Kennedy, & Generally, 2005; Hammer, 1996; Kerr, Walsh, & Marshall, 2001). But what mechanisms of music-induced emotions are most responsible for the efficacy of music therapy interventions? How do these mechanisms differ between different music therapy interventions? And how can the neurobiological effects of music influence the client-therapist relationship? …