Major depressive disorder (MDD) is a highly prevalent and disabling disorder associated with persistent low mood, loss of the capacity to experience pleasure (i.e. anhedonia), reduced social functioning, and impaired quality of life. MDD is estimated to affect approximately 2% of Canadian women and 1% of Canadian men at any point in time. The World Health Organization affirms that depression is the leading cause of disability worldwide, with increasing global economic impact.

Standard treatments for depression include basic psychosocial support combined with antidepressant medication or psychotherapy. It has been observed, however, that only 50% of individuals respond to psychological treatment, and only 30-40% of patients achieve full remission after initial treatment with antidepressants. Music- and sound-related therapies have the potential to serve as adjuncts to, or facilitators of, medication.

In this study we will examine the effectiveness of a new therapeutic tool, known as Rhythmic Sensory Stimulation, as an adjunctive treatment for Major Depressive Disorder. Rhythmic Sensory Stimulation is a non-invasive brain stimulation technique that uses periodic pulses of light, sound, or tactile stimulus, to induce changes in the patterns of brain activity. Participants in this study will undertake 30 minutes of daily music intervention self-administered at home, for 5 days per week, for a total of 5 weeks. We will assess depression symptoms, sleep quality, quality of life, and brain activity pre- and post-treatment.

The results of the present study will help to better understand the effectiveness of Rhythmic Sensory Stimulation to the treatment of mood disorders, and contribute to the development of future studies to investigate the neural driving effects of therapies based on Rhythmic Sensory Stimulation.

Major depressive disorder (MDD) is a highly prevalent and disabling disorder associated with persistent low mood, loss of the capacity to experience pleasure (i.e. anhedonia), reduced social functioning, and impaired quality of life. MDD is estimated to affect approximately 2% of Canadian women and 1% of Canadian men at any point in time. The World Health Organization affirms that depression is the leading cause of disability worldwide, with increasing global economic impact.

Standard treatments for depression include basic psychosocial support combined with antidepressant medication or psychotherapy. It has been observed, however, that only 50% of individuals respond to psychological treatment, and only 30-40% of patients achieve full remission after initial treatment with antidepressants. Music- and sound-related therapies have the potential to serve as adjuncts to, or facilitators of, medication. Several recent systematic reviews have concluded that music is an effective therapeutic tool with significant results on improving global state, symptoms, and overall functioning, and is also well-accepted by patients.

The goal of this project is to evaluate the effectiveness of music and rhythmic sensory stimulation with low-frequency sounds as an adjunctive therapy for depression. Through a systematic collection of clinical, behavioural and electrophysiological measures, the project also aims to determine the possible mechanisms that underlie the effects of music- and sound-based therapies on symptoms of MDD. In addition to measures of depression severity and symptoms, we are also interested in secondary behavioral measures addressing possible confounding variables, such as anhedonia, quality of life, and individual differences in how people experience reward and pleasure associated with music. These assessments will allow an initial investigation of the neural correlates of the therapeutic effects of music in the treatment of depression, which is greatly warranted to better understand the efficacy of music- and sound-based treatments.

Inclusion Criteria:

• Outpatients 18 to 60 years of age.
• Meet DSM-IV-TR criteria for major depressive episode (MDE) in major depressive disorder (MDD) without psychotic features, as determined by clinician assessment.
• Episode duration > 3 months.
• MADRS score ≥ 15 (mild to severe symptoms intensity).
• Fluency in English, sufficient to complete the interviews and self-report questionnaires.
• Satisfactory hearing bilaterally based on self-report.

Exclusion Criteria:

• Any Axis I diagnosis (other than MDD), and MDD with psychotic features,that is considered the primary diagnosis.
• Fibromyalgia diagnosis (FIQR score ≥ 39).
• Bipolar-I or Bipolar-II diagnosis (HCL score ≥ 14).
• Presence of a significant Axis II diagnosis (borderline, antisocial), judged as being primary based on clinician assessment.
• High suicidal risk, defined by clinician judgment.
• Substance dependence/abuse in the past 6 months.
• Presence of significant neurological disorders, head trauma, or other unstable medical conditions.
• Acute and active inflammatory conditions, rheumatoid arthritis, osteoarthritis, autoimmune disease.
• History of epilepsy, seizures.
• Hemorrhaging or active bleeding.
• Hearing impairment.
• Thrombosis or heart diseases, including hypotension, arrhythmia, pacemaker, angina pectoris.
• Pregnant or breastfeeding.
• Recovering from recent accident with prolapsed vertebral disc, back or neck injury.
• Started psychological treatment within the past 3 months with the intent of continuing treatment.
• Patients who have changed medication or adjusted medication dosage within 4 weeks.

Data will be stored and shared through Ontario Brain Institute platform (BRAIN-Code).