Depression is a common mental disorder caused by an interaction of social, psychological, and biological factors that can occur in anyone [1]. The number of people who suffer from depression worldwide is estimated to be 260 million, with Chinese people making up 21.3 % of this group [2]. Depression is a major issue for older adults, and its prevalence is rising [3]. The cost of nursing care and finances are increased by the fact that older adults with depression have suicide and mortality rates that are significantly greater than those of the general population [4,5]. According to the Global Burden of Disease Study 2019, mental disorders are still among the top 10 causes of burden globally; depressive disorders rank first in the burden of mental disorders and thirteenth in the global burden of disease [6]. In an aging society, depression has emerged as a public health concern [7].

Depressive mood is the primary sign of depression, and other symptoms include low mood, loss of enjoyment, low energy, sadness, insomnia, and suicidal tendencies [1]. Numerous conditions, such as anxiety disorders, dementia, cancer, hypertension, coronary heart disease, diabetes, and more, interact with depression [8]. According to research [9], 85 % of people with depression also have considerable levels of anxiety, and depressive disorders and anxiety disorders frequently coexist. Major depressive disorder patients frequently have cognitive impairment, which has an impact on their personal and professional lives [10]. Additionally, depression is a well-known risk factor for cardiovascular illness, which raises patients' chances of developing hypertension [11].

Currently, drug therapy or psychotherapy are the main forms of treatment for depression, with various complementary therapies serving as an adjunct. However, older adults require safer support options due to their low tolerance of medications, poor compliance with psychotherapy, and higher rates of chronic physical illnesses [12]. Therefore, researchers are actively looking into novel approaches to treating depression, such as music therapy (MT) [13].

Music therapy is an interdisciplinary subject that integrates psychology, medicine, musicology, physical biology, and special education. As a highly structured auditory language, music is composed of multiple acoustic elements such as pitch, loudness, rhythm, timbre, melody, and harmony, which constitute different musical existence according to the time pattern of simultaneity and sequence, and produce multidimensional stimulation of cognition, emotion, and sensory nerve [14]. Music therapy is described as "the use of music or musical elements by certified music therapists to promote communication, learning, and expression to meet the individual's physical, emotional, psychological, social, and cognitive needs" [15]. Depending on the intervention modality, music therapy can be either active or passive. Active music therapy involves patients actively participating in singing, playing instruments, and improvising in the presence of a therapist [16]. Passive music therapy involves patients primarily listening to and enjoying music while passively listening to the music selected by the therapist [17].

However, different music therapy prescriptions (such as active and passive music therapy) have varying results for various patients [18,19]. It is important to conduct further research on the most effective interventions for depressed older adults. The most recent systematic review [20] searched until October 2021, included only one relevant literature from that year, and limited the language to English, ignoring literature in other languages. It is necessary to update this evidence due to the publication of several randomized controlled trials (RCTs) of music therapy in older adults with depression in the last two years. The purpose of this review is to evaluate the therapeutic effects of music therapy and the effects of specific interventions on older adults with depression.