The effect of music therapy for patients with chronic pain: systematic review and meta-analysis

Abstract

Aims

To assess the effect of music therapy in improving chronic pain (CP), anxiety, depression, and quality of life using randomized controlled trials, and to explore the role of various moderators in MT effectiveness.

Design

Systematic review and Meta-analysis.

Methods

We systematically searched four electronic databases for randomized controlled trials that investigated the effects of music therapy on chronic pain, anxiety, depression, and quality of life. We performed a Cochrane risk-of-bias assessment and calculated the pooled standard mean difference in the outcomes of the test and control groups after the intervention period.

Results

Nine randomized controlled trials were retrieved that included a total of 787 patients. Music therapy significantly reduced CP in the test group compared with that in the control group post-intervention and depression, no evidence was observed for improvement in anxiety and quality of life. Subgroup analysis reveals that MT is most effective when interventions are conducted in developed countries, targeting CNMP or cancer pain patients in health centers. The therapy is most effective when patients select their own music, use instruments or earphones, and receive treatment from trained professionals, with an ideal duration of 20 min, except in studies involving postoperative CP or those conducted in developing countries.

Conclusions

Music therapy effectively reduces CP and depression, but has limited effects on anxiety and quality of life. Its effectiveness varies depending on the specific conditions and CP categories of patients, with differences observed between developing and developed countries. Future research should focus on developing standardized guidelines for music therapy, exploring its long-term effects on pain, anxiety, and quality of life, and conducting high-quality, multicenter RCTs in developing countries to support its global adoption in CP management.

Introduction

Chronic pain (CP) has been defined by the International Association for the Study of Pain Research as persistent or recurrent pain that lasts for ≥ 3 months, which has been declared a disease in 2000 [1]. Approximately 25% of people worldwide will, at some point, suffer from chronic pain. In many countries, the incidence of CP in the general population is 20 ~ 45%. In the US alone, up to 12 million people have experience CP. The high prevalence and refractory nature of CP, in conjunction with the negative consequences of pain medication dependence, can lead to significant medical, social, and economic consequences, relationship issues, loss of productivity, and high healthcare costs [2,3,4]. The World Health Organization (WHO) estimates CP as one of the leading causes of Years Lost to Disability globally. However, the existing treatment has modest efficacy, limited tolerability, and important safety risks. CP is frequently accompanied by psychiatric disorders such as pain medication addiction and depression, which complicate the treatment [5]. In addition, pain can significantly diminish one's quality of life owing to its negative impact on every aspect of life [6, 7]. In 2016, the Centers for Disease Control and Prevention (CDC) issued recommendations to reduce the use of opioids and increase the use of non-pharmacological therapies for CP treatment [8, 9]. A recent study in the Lancet demonstrated that opioids currently are no longer considered to be a first-line treatment for any form of chronic pain, and many guidelines do not recommend them at all in some populations (e.g., young individuals with non-cancer pain), and it also have demonstrated that the rates of alternative treatments continue to increase [10]. Viable complementary therapy or alternatives to opioids are promising treatment options for patients with CP. The US Food and Drug Administration (USFDA) issued policy statements calling for the development of novel therapies with reduced potential for misuse [5].

The World Federation of Music Therapy (MT) defines MT as the use of music and musical elements (sound, rhythm, melodies, or harmonies) to ease and promote communication, relationships, learning, movement, expression, organization, and other relevant therapeutic objectives, thereby solving physical, emotional, mental, social, and cognitive needs [11]. Studies have shown that MT can benefit patients suffering from pain [11,12,13]. Currently, MT, as an important viable complementary and alternative treatments, has been widely used in the clinical management of diseases, but it is not widely used in patients with CP and the methodological quality of some trials is typically poor. In addition, the evidence regarding the effects of MT on CP and depression, anxiety, and quality of life has yet to be reported. Thus, we conducted a systematic review and Meta-analysis to evaluate the effectiveness of MT in patients with CP using published randomized clinical trials (RCTs) data and outcome indicators, improvement in CP was the primary outcome, and secondary outcomes included alleviation of depression and anxiety as well as improved quality of life. In addition, we sought to explore the role of various moderators in MT effectiveness, aiming to provide a basis for the development of therapeutic guidelines, clinical pain interventions, and the application of music therapy for CP patients.

Methods

Registration and protocol

We conducted this systematic review and meta-analysis following the Cochrane Handbook for Systematic Reviews of Interventions [14] and adhered to the PRISMA guidelines in preparing the manuscript. A PROSPERO protocol (CRD42022348688) was registered prior to starting the review.

Eligibility and exclusion criteria

The inclusion criteria were as follows: (1) Types of study participants: participants with all forms of CP, and the eligibility was not restricted by diagnostic status, medication usage, or any other characteristics (such as age or gender); (2) Types of interventions: the experimental group received MT; (3) Types of control: The comparison group accepted conventional control measures such as usual care, standard care and placebo intervention;(4) Outcome indicators: studies assessed CP as an outcome; (5) Study type: RCTs; and (6) Language: published in English. Exclusion criteria included: (1) duplicate publications, and (2) protocols, reviews, theoretical literature, case reports, dissertations, and conference papers.

Search strategy

We identified studies that evaluated the effectiveness of MT for CP patients using PubMed, Web of Science, Embase, and Cochrane Library. The search strategy was customized slightly for different databases. Search terms were as follows: “Music Therapy" OR “Music" OR “Musical" OR “Music Intervention" OR “sing" OR “Therapy, Music" And “Chronic Pains" OR “Pains, Chronic" OR “Pain, Chronic" OR “Widespread Chronic Pain" OR “Chronic Pain, Widespread" OR “Chronic Pains, Widespread" OR “Pain, Widespread Chronic" OR “Pains, Widespread Chronic" OR “Widespread Chronic Pains". After the electronic search, we searched potential papers from the reference lists of included relevant reviews, and previous meta-analyses. The PubMed search strategy was as follows:

• #1 “Chronic pain” [Mesh]

• #2 Chronic Pains [Title/Abstract] OR Pains, Chronic [Title/Abstract] OR Pain, Chronic [Title/Abstract] OR Widespread Chronic Pain [Title/Abstract] OR Chronic Pain, Widespread [Title/Abstract] OR Chronic Pains, Widespread [Title/Abstract] OR Pain, Widespread Chronic [Title/Abstract] OR Pains, Widespread Chronic [Title/Abstract] OR Widespread Chronic Pains [Title/Abstract]

• #3 #1 OR #2

• #4 “Music therapy” [Mesh]

• #5 Music therapy [Title/Abstract] OR Music [Title/Abstract] OR Musical [Title/Abstract] OR Music Intervention [Title/Abstract] OR Sing [Title/Abstract] OR Therapy, Music [Title/Abstract]

• #6 4 OR #5

• #7 #3 AND #6

Study selection

Duplicate literature was identified using EndNote X9 and manually removed. Based on inclusion and exclusion criteria, titles and abstracts were screened to exclude documents that clearly did not meet the criteria. Full texts were then reviewed to further exclude any ineligible studies. Two reviewers independently extracted key information: first author, publication year, country, CP category, age, sex, sample size, intervention content and control treatments, music selection, tools, outcome measures, intervention equipment, form, frequency, timing, qualifications, and music genre. Disagreements were resolved by consulting a third reviewer for the final decision.

Quality assessment

Studies that met the inclusion criteria underwent a rigorous quality assessment to evaluate bias risk for each outcome. Two independent reviewers assessed the studies using the Cochrane Collaboration’s risk of bias tool (Cochrane Handbook 5.3) [14], covering key domains like sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential biases. Each study was assigned a risk level: low, unclear, or high. Quality grades were designated as A (low bias), B (moderate bias), or C (high bias). Studies rated A or B were included in the analysis, while those rated C were excluded due to high bias risk.

The two reviewers conducted evaluations independently, compared their results, and resolved disagreements through discussion or, if needed, by consulting a third party. The final evidence synthesis was performed using the John Hopkins Evidence Synthesis and Advice Tool, with meta-analysis findings interpreted in light of the identified bias risks.

Data synthesis and analysis

The meta-analysis was conducted using RevMan 5.4. Statistical effectiveness was analyzed using Cohen's standardized mean difference (SMD) with 95% confidence intervals (CI) for categorical and continuous data. Heterogeneity was assessed using Cochran's Q test and the I² statistic, with I² levels categorized as low (25%), moderate (50%), and high (75%). SMD was applied to combine results across different assessment tools, while mean difference (MD) was calculated for consistent tools, such as the Visual Analog Scale (VAS) and numeric rating scale (NRS). A funnel plot assessed publication bias.

To explore the impact of various moderators on MT effectiveness and investigate sources of heterogeneity across studies, we performed subgroup analyses. The subgroup variables included countries (developing countries, developed countries), sample sizes (≥ 50– < 80; ≥ 80– < 120; ≥ 120), mean ages (< 50, 50–55, > 55), settings (hospital and health/medical center), CP categories (CNMP, cancer, postoperative CP), intervention equipment (musical instrument, earphone, loudspeaker&Earphone, CD/Tape, Player&Headphone), intervention content (PMT (recorded music) and AMT (live music)), intervention durations (minutes) (20, 30, 60), music selection (patient, music therapists/nurses), qualifications (music therapists, trained therapists), pain assessment tools (NRS, VAS).

Results

Study selection and identification process

A total of 1,128 records were identified through database searches: Web of Science (n = 415), Embase (n = 222), PubMed (n = 214), Cochrane Library (n = 235), CNKI (n = 19), Wanfang Database (n = 16), and VIP (n = 7). After removing duplicates, 538 records remained. Of these, 469 records were further assessed, and 232 were excluded due to incorrect study types, while 227 were deemed irrelevant. A total of 7 studies were included based on the reference lists of other publications. After full-text review, 69 publications were excluded for various reasons: 19 for acute pain, 24 for being combined with other therapies, 2 for being in other languages, 5 for being protocol articles, 7 for incomplete data, and 12 for unavailable full texts. Ultimately, Nine studies [15,16,17,18,19,20,21,22,23] were included in the meta-analysis, and two studies were conducted by the same researchers [20, 21]. Figure 1 presents the flow diagram of study selection and identification.

Fig. 1

Flow diagram of study selection and identification

Study characteristics

The included studies were published between 2006 and 2021, with sample sizes ranging from 42 to 198. These studies were from five different countries and regions: USA (n = 3) [15, 18, 23], China (n = 3) [19,20,21], France (n = 1) [17], Italy (n = 1) [16], Spain (n = 1) [22] and six (66.67%) studies were conducted in developed countries and three (33.33%) studies were conducted in developing countries. Regarding the sample size, five studies (55.56%) had sample sizes between ≥ 50 and < 80, 2 studies (22.22%) had sample sizes between ≥ 80, < 120, and two studies (22.22%) had sample sizes of ≥ 120.

Regarding the categories of CP, CNMP was reported in three studies (33.33%), chronic cancer pain and postoperative CP were reported in two studies (total n = 4, 44.44%); fibromyalgia was reported in one study (11.11%), and one study did not specify a medical condition or source of the CP (11.11%). In terms of the pain assessment tool, VAS was used as an assessment tool in seven studies (77.78%), while NRS (22.22%), and SF-MPQ (22.22%) were used in two studies. One study used NRS and FLACC together for pain assessment (11.11%). In terms of the quality of life, SF-36 was used in two studies (22.22%). In terms of depression and anxiety, HADS and BDI were used in two studies (22.22%) and one study (11.11%), respectively.

In terms of intervention durations, two studies (22.22%) used 60-min sessions, four studies (44.44%) applied 30-min sessions, and two studies (22.22%) used 60-min sessions. In terms of the measurement time, three studies (33.33%) measured before and after the intervention, two studies (22.22%) measured baseline, 4, 8, and 12 weeks (follow-up at 12 weeks); two studies (22.22%) measured six months after surgery, and one study (11.11%) measured baseline, 4, 8, and 12 weeks (follow-up at 12 weeks). One study (11.11%) measured 0, 5, 10, 60, and 90 days. Regarding the qualification, three studies were conducted by qualified music therapists (33.33%) and trained nurses(33.33%), and nurse-researcher teams; one study had no report (total n = 3, 33.3%). In terms of the music selection, it was selected by patients in seven studies (77.78%) and selected by music therapists and nurses were two studies (22.22%). In terms of the intervention setting, four studies (44.44%) were in a hospital, one study (11.11%) was at home, one study was at home, and one study was at a hospital, clinic, medical center, and nurse-managed health center, respectively (total n = 4, 44.44%). In terms of the music genre, six studies(66.67%) used three genres music (n = 22.22%), different genres (n = 22.22%) and instrumental music (n = 22.22%), followed by vocal improvisation (n = 1, 11.11%), mixed music (n = 1, 11.11%) and classical (n = 1, 11.11%). Among the three and mixed music genres: two studies (22.22%) used classical music, while three studies used jazz and world music (n = 1, 11.11%), folk songs, Buddhist music and instrumental music (n = 1, 11.11%) and salsa music (n = 1, 11.11%), respectively.

In terms of the music equipment, five studies (55.56%) used headphones, three studies (33.33%) used musical instruments, and one study used loudspeakers, tape players, and CDs (total n = 3, 33.33%). Regarding the music intervention type, eight studies (88.89%) used PMT, and one study (11.11%) used AMT. There were seven individual intervention studies (77.78%) and 2 group intervention studies (22.22%). Six studies (66.67%) had recorded music, one study (11.11%) had live music, and one study (11.11%) had vocal MT. All control groups were treated with standard care (n = 9,100%). In addition, in terms of the intervention duration, four studies (44.44%) were 30 min/time, three studies (33.33%) were 60 min/time, and two studies (22.22%) were 20 min/time. Regarding the frequency of intervention, seven studies (77.78%) were once a day, one study was two times/day, and eight times/a week (total n = 2, 22.22%). The characteristics of the included studies are summarized in Table 1.

Table 1 Characteristics of clinical trials included in this meta-analysis

Risk of bias

High-risk studies were excluded [24,25,26,27,28]. The risk assessment of bias in the included studies is shown in Figs. 2 and 3. Nine studies [15,16,17,18,19,20,21,22,23] had eight items mentioning the production of random order (88.9%), and one study did not describe the specific random method (11.1%). Six studies reports were hidden in allocation (66.7%), three studies did not mention the hidden plan (33.3%), and the experimental design of the object of the blindness of MT was difficult to apply. Six studies mentioned that the research objects and interviewees were blinded applied (66.7%). Three studies did not specify the blindness (33.3%) of the research objects and interviewees; five studies performed the results of the evaluation (55.6%), and the four studies did not describe whether the results were blind (44.4%). All nine studies are complete (100%) for the ending indicators, and the possibility of selective report results is low (100%); the risk of bias from other aspects is low (100%). The evidence synthesis of the included studies is summarized in Table 2.

Fig. 2

Risk-of-bias graph and risk

Fig. 3

Risk of bias in individual studies

Table 2 Evidence synthesis

The overall effects of MT

Nine studies (n = 787) [15,16,17,18,19,20,21,22,23] evaluated the effects of MT on CP using a random-effects model. Meta-analysis of the random effects model showed that the MT reduced CP [15,16,17,18,19,20,21,22,23] (9 RCTs, SMD = −0.51, 95% CI: −0.72, −0.30, P < 0.00001, I² = 62%; Fig. 4), depression [15, 17, 22, 23] (4 RCTs, SMD = −0.83, 95% CI:−1.44 to −0.22, P = 0.0001, I² = 83%; Fig. 5), while it did not show a positive effect on anxiety [15, 17] (2 RCTs, MD = −3.31, 95%CI (−8.21, 1.58, P = 0.18, I² = 90%, Fig. 6) and quality of life [20, 21] (2 RCTs, MD = 2.59, 95%CI (−0.47, 5.65), P = 0.1, I² = 77%, Fig. 7).

Fig. 4

Effects of MT to reduce CP [15,16,17,18,19,20,21,22,23]. SD = standard deviation, CI = confidence interval, IV = inverse variance, I² = inconsistency

(note: Lin et al. conducted two studies [20, 21]. Lin 2021a study focus on effect of MT on the Midterm Quality of Life of Patients after Mechanical Valve Replacement, while Lin 2021b study focus on the effect of MT on Quality of Life in Adolescents after Transthoracic Occlusion of Ventricular Septal Defects; Lin 2021a-a = The first study measured data using the VAS, Lin 2021a-b = The first study measured data using the SF-MPQ; Lin 2021b-a = The second study measured data using the VAS, Lin 2021b-b = The second study measured data using the SF-MPQ; Sandra 2006* = MPQ-S(Patterning Music, PM), Sandra 2006** = MPQ-S(Standard Music, SM), Sandra 2006*** = VAS(SM), Sandra 2006**** = VAS(PM))

Fig. 5

Effects of MT to reduce depression. SD = standard deviation, CI = confidence interval, IV = inverse variance, I² = inconsistency

(note: Sandra 2006* = SM, Sandra 2006** = PM)

Fig. 6

Effects of MT to reduce anxiety. SD = standard deviation, CI = confidence interval, IV = inverse variance, I² = inconsistency

Fig. 7

Effects of MT on improving quality of life. SD = standard deviation, CI = confidence interval, IV = inverse variance, I² = inconsistency

(note: BP = bodily pain, GH = general health, MH = mental health, PF = physical functioning, RE = role-emotional, RP = role-physical, SF = social functioning, VT = vitality)

Sub-group analyses

Countries

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different countries. These countries were divided into two groups for subgroup analysis: developing countries (n = 3) [19,20,21], and developed countries (n = 6) [15,16,17,18, 22, 23]. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in developed countries group (SMD = −0.73, 95% CI: −0.16 to −0.04, P < 0.0001, I² = 74%, but MT did not improve CP in developing countries group (SMD = −0.39, 95% CI: −0.89 to 0.11, P < 0.13, I² = 64%), Table 3.

Sample sizes

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different sample sizes, which were divided into three groups for subgroup analysis: ≥ 50 and < 80 (n = 5), ≥ 80 and < 120 (n = 2), ≥ 120 (n = 2). The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in all three groups (SMD = −0.68, 95% CI: −1.20 to −0.15, P = 0.010, I² = 76%; SMD = −0.46, 95% CI: −0.72 to −0.20, P = 0.0004, I² = 0%; SMD = −0.61, 95% CI: −0.96 to −0.26, P = 0.0006, I² = 57%), Table 3.

Mean ages

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different ages, which were divided into three groups for subgroup analysis: < 50 (n = 3); 50 ~ 55 (n = 4) and ≥ 60 (n = 2) mean age group. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in all three groups (SMD = −0.54, 95% CI: −0.85 to −0.24, P = 0.0004, I² = 0%; SMD = −0.71, 95% CI: −1.32 to −0.10, P = 0.002, I² = 85%; SMD = −0.54, 95% CI: −0.84 to −0.24, P = 0.0004, I² = 17%), Table 3.

Settings

6 RCTs (N = 456) measured the effect of MT on CP in different settings, which were divided into two groups for subgroup analysis: hospital (n = 2), health/medical center (n = 2); the results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in two groups (SMD = −0.45, 95% CI: −0.83 to −0.07, P = 0.02, I² = 58%; SMD = −0.66, 95% CI: −1.04 to −0.27, P < 0.0009, I² = 35%), Table 3.

CP Categories

7 RCTs (N = 494) [15,16,17, 19,20,21, 23] measured the effect of MT on CP in different categories, which were divided into three groups for subgroup analysis: CNMP (n = 3) [15, 17, 23], Cancer (n = 2) [16, 19], Postoperative (n = 2) [20, 21]. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in CNMP and Cancer groups (SMD = −0.59, 95% CI: −0.88 to −0.28, P = 0.0001, I² = 0%; SMD = −0.81, 95% CI: −0.12 to −0.50, P < 0.00001, I² = 0%), but MT did not improve Postoperative CP (SMD = −0.12, 95% CI: −0.46 to 0.21, P = 0.470, I² = 0%), Table 3.

Intervention Equipment

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different equipment, which were divided into four groups for subgroup analysis: musical instrument (n = 3), earphone (n = 2), loudspeaker&earphone (n = 2), CD/Tape player&Headphone (n = 2). The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in musical instrument and earphone groups (SMD = −0.66, 95% CI: −0.88 to −0.28, P = 0.0001, I² = 0%; SMD = −0.81, 95% CI: −0.12 to −0.50, P = 0.0006, I² = 57%), but MT did not improve Loudspeaker&Earphone (SMD = −0.12, 95% CI: −0.46 to 0.21, P = 0.47, I² = 0%) and CD/Tape player&Headphone groups (SMD = −1.09, 95% CI: −2.24 to −0.06, P = 0.06, I² = 85%), Table 3.

Intervention Content

8 RCTs (N = 648) [16,17,18,19,20,21,22,23] measured the effect of MT on CP in different MT methods. These MT methods were divided into two groups for subgroup analysis: PMT (recorded music) (n = 6) [17, 19,20,21,22,23] and AMT (live music) (n = 2) [16, 18]. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in two groups (SMD = −0.45, 95% CI: −0.68 to −0.22, P = 0.0001, I² = 69%; SMD = −0.79, 95% CI: −1.04 to −0.54, P < 0.00001, I² = 17%), Table 3.

Intervention Durations

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different MT times, which were divided into three groups for subgroup analysis: 20 min (n = 2) and 30 min (n = 4) and 60 min (n = 3). The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in three groups (SMD = −0.54, 95% CI: −0.80 to −0.28, P < 0.0001, I² = 13%; SMD = −0.48, 95% CI: −0.89 to −0.08, P < 0.02, I² = 67%; SMD = −0.85, 95% CI: −1.65 to −0.06), P = 0.04), Table 3.

Music Selection

9 RCTs (N = 747) [15,16,17,18,19,20,21,22,23] measured the effect of MT on CP in different music selections, which were divided into two groups for subgroup analysis: patient (n = 7) and music therapist/nurse (n = 2). The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in two groups (SMD = −0.47, 95% CI: −0.68 to −0.22, P < 0.0001, I² = 35%; SMD = −1.18, 95% CI: −2.10 to −0.26, P = 0.01, I² = 83%, Table 3.

Qualifications

6 RCTs (N = 560) [15,16,17,18,19,20] measured the effect of MT on CP in different MT qualifications, which were divided into two groups for subgroup analysis: music therapist (n = 3) [15, 18, 20] and trained nurse (n = 3) [16, 17, 19]. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in two groups (SMD = −0.28, 95% CI: −0.51 to −0.06, P < 0.05, I² = 0%; SMD = −0.49, 95% CI: −0.80 to −0.17, P < 0.05, I² = 0%), Table 3.

Pain Assessment Tools

5 RCTs (N = 447) [15,16,17,18, 22] measured the effect of MT on CP in different pain assessment tools. These tools were divided into two groups for subgroup analysis: VAS (0–10) (n = 3) [16, 17, 22] and NRS (n = 2) [15, 18]. The results of our subgroup meta-analysis showed that compared with the control group, MT significantly improved CP in two groups (SMD = −1.55, 95% CI: −2.32 to −0.79, P < 0.0001, I² = 64%; SMD = −1.29, 95% CI: −2.06 to 0.52, P = 0.001, I² = 80%), Table 3.

Table 3 Subgroup analyses of music-based intervention to reduce CP

Publication bias

We assessed the publication bias of CP by visual examination of funnel plots. The funnel plots show that all the research generally processes upside-down functions are left and right, and the publication bias is low, Fig. 8.

Fig. 8

Funnel plot of CP

Discussion

Our meta-analysis demonstrated that MT was effective in alleviating CP and depression, but not anxiety or quality of life. Specifically, MT significantly reduced CP (9 RCTs, SMD = −0.51, 95% CI: −0.72, −0.30, P < 0.00001) and depression (4 RCTs, SMD = −0.83, 95% CI:−1.44 to −0.22, P = 0.0001), while no significant effects were observed for anxiety (2 RCTs, MD = −3.31, 95%CI: −8.21, 1.58, P = 0.18) or quality of life (2 RCTs, MD = 2.59, 95%CI: −0.47, 5.65, P = 0.1). Subgroup analysis further revealed that the effectiveness of MT varied significantly depending on different intervention conditions. Notably, the most pronounced therapeutic effects were observed in studies conducted in developed countries, targeting patients with CNMP or cancer pain, and implemented in health/medical centers. Additionally, interventions were more effective when patients selected their own music, used musical instruments or earphones, and received therapy from professionally trained nurses or music therapists. The optimal intervention duration was 20 min, and pain assessment tools such as VAS or NRS were commonly used. However, MT showed limited effect in developing countries, for postoperative CP, or when loudspeakers and CD/tape players were used. The high-quality RCTs included in our analysis, along with consistent reporting of blinding and allocation concealment, support the reliability of these results. These insights provide valuable evidence for developing future clinical guidelines and optimizing MT for specific CP populations and settings.

Opioids are an effective means of relieving CP in many patients; however, certain doses or long-term use can cause mental activity effects and drug addiction. Regarding drug abuse in developed countries. Cole et al. [29] reviewed 17 randomized controlled studies and provided support for the use of music as an adjuvant approach for pain treatment (acute pain, CP, and cancer pain control). This indicates that future studies can clinically apply MT as non-medication-assisted therapy or MT combined with drugs in CP groups to relieve CP and depressive symptoms, which will help in reducing the dose and intake of painkillers. However, ColeLc et al. [29] only conducted a systematic review without further meta-analysis. Our meta-analysis showed that MT was effective in alleviating CP and depression. This may be related to the following mechanisms: (1) It is hypothesized that MT stimulates the limbic system related to emotions, regulates the function of the cerebral cortex, and promotes the release of endorphins in the pituitary gland [30]. (2) MT activates areas of the brain associated with reward, emotion, and arousal, such as the nucleus accumbens, amygdala, anterior insula, cingulate cortex, orbitofrontal cortex, and dorsomedial thalamus, through which emotional and cognitive pain regulation can be achieved [31]. Previous studies [26,27,28] show that although patients with CP have different conditions, disease courses, social environments, and psychological states, most patients with CP have symptoms of anxiety and depression, which seriously affect their quality of life. The results of our meta-analysis suggest that MT can reduce depression in patients with CP, which is consistent with the results of Garza-Villarreal et al. [12]. Music can reduce the basal metabolic rate, oxygen consumption per minute, blood pressure, and heart rate, and the use of alcohol and painkillers to relax muscles and relieve anxiety. A meta-analysis [32] found that MT produced clinically beneficial outcomes for improving the quality of life of patients with pain. However, no evidence in this study suggested that MT can improve the anxiety and quality of life of patients with CP, which may be related to the small number of included studies and small sample size. Among the included studies (n = 9), only two [15, 17] reported anxiety and quality of life scores, and the meta-analysis results should be interpreted with caution. As the evaluation of the quality of life includes many aspects, MT may improve patients’ quality of life with CP, which needs to be confirmed by conducting further research.

Our study identified several key aspects in existing studies. Specifically, the number of such studies in developed countries was significantly higher than those conducted in developing countries. The MT settings were mostly present in the hospital. The sample size mostly included patients aged between 50 and 80 years. The CP category (CNMP) was the main category of CP. Patients choose recorded music over live or vocal MT, they choose music significantly more often than interveners who choose music for them. The individual intervention was significantly more common than the group intervention. Headphones were selected as the equipment. The intervention frequency was highest once a day. Thirty min/session was the most preferred intervention duration. Music therapists and nurses were qualified. Three genres or different genres and instrumental music were chosen the most. A total of three different scales were used to evaluate the CP of the participants, and NRS and VAS were the most frequently used scales. VAS applications were significantly higher than those of NRS, and most studies chose pre- and post-intervention measurements. MT is divided into three types according to the patient’s involvement [13]. PMT is for the patients who are not required to participate actively in music performances or singing activities; only listening is expected. A professional music therapist usually plays music for patients and guides them to achieve a spiritual relaxation experience [33]. AMT refers to the treatment of patients with the method of cooperating with the patient to regulate their emotions in the form of lyrics, playing instruments, or singing and dancing to gradually improve the patient's ability to adapt to the outside world [34]. It is worth noting that our study varied greatly in terms of the number of active and passive music therapies, and more studies were used to improve CP using PMT (n = 8). AMT was only conducted in one study. These findings provide valuable insights into the implementation of music therapy and research design, while also highlighting areas that future studies should focus on. Our subgroup analysis found that MT was more effective in reducing certain categories of CP, such as cancer and chronic non-malignant pain, without heterogeneity and had a significant positive effect in developed countries and across all age groups, sample sizes and types intervention methods, qualifications, and pain assessment tools. However, the effect of MT is not significant in developing countries, which may be due to the small number of music therapists in developing countries, shortage of medical personnel trained in MT, lack of norms in the implementation process, and a small amount of literature. Moreover, interventions conducted in health and medical centers, where patients select their own music and use instruments or earphones, and where the intervention is administered by trained nurses with a duration of 20 min, showed the most effective results. Additionally, due to the lack of relevant research, a few questions remain unresolved, including which is more effective: individual MT versus group MT, or the effect of home-based interventions. Moreover, the effectiveness of MT for CP types beyond the three studied in our research remains uncertain. Therefore, future high-quality RCTs are needed to explore the underlying mechanisms of the findings and address these unanswered questions.

The heterogeneity observed in the meta-analysis and subgroup analysis may be attributed to the following factors: (1) There is still a lack of corresponding guidelines for implementing standard intervention procedures for patients with CP. The specific intervention measures adopted by different studies vary and the types of interventions for patients with CP are relatively simple. This issue may be more serious in developing countries, and there are no high-quality RCTs on this topic which have been published in China. (2) The evaluation criteria are not uniform, and the lack of standardized measurement methods cannot be compared with the results obtained from different intervention types, and the results may be biased. In our subgroup analysis, we noticed that the heterogeneity of VAS is relatively high, which may be due to differences in the 0–10 and 0–100 ranges of VAS. This suggests that different studies used VAS scales with significantly varying score ranges, which could lead to differences in the assessment of pain intensity, thereby affecting the measurement of pain relief outcomes. Moreover, some studies may have employed different methods for score conversion or classification, further contributing to the heterogeneity of the results. Therefore, to reduce the heterogeneity introduced by VAS scores, it is recommended that future studies standardize the VAS score range and use standardized conversion methods for comparison. The range of NRS is consistent, which did not reveal heterogeneity. (3)The categories and severity of CP in the subjects were unclear. In this study, the subgroup analysis of various categories of CP did not reveal any heterogeneity. Therefore, the meta-analysis results of this study must be interpreted with caution, and an additional moderating variable analysis or meta-analysis is required to identify various sources of heterogeneity. To improve the quality of CP intervention, future studies should develop standardized intervention guidelines, unify evaluation criteria, and use consistent measurement tools (such as the VAS scale) to reduce heterogeneity. Additionally, it is important to clarify patient classifications and severity levels, and conduct subgroup analyses to better understand the effects of interventions.

We searched the related databases and found that there are fewer related meta-analyses at present, which may be related to the following two aspects. First, the WHO revised the International Disease Classification in 2018, which has divided CP into seven categories [1]. Previous to that, the classification and definition of CP was not clear, and it was difficult to evaluate and analyze it correctly. Second, because the effect of MT for treating patients with CP was not fully interpreted, there was no sufficient evidence to prove that music can relieve CP. Lee et al. [12] in their meta-analysis divided pain into acute pain, CP and programmed pain, their results showed that MT had a slightly stronger effect on acute/procedural pain (MD = −1.15) than on chronic/cancerous pain (MD = −0.97); however, the CP category included cancer pain alone, the categories of CP in this study are relatively singular (almost only cancer pain), which is not representative of the CP categories. A meta-analysis [2] only included RCTs involving adults aged 18–70 years and showed no significant difference in the results of MT used for the treatment of different categories of CP, their study did not include all categories of CP and the findings had significant heterogeneity, there is less evidence of the effectiveness of MT for the treatment of all categories of CP. Our study included all CP categories and excluded all research on acute pain. In contrast, our study included all categories of CP while excluding acute pain, and it conducted detailed subgroup analyses, providing a more comprehensive and representative assessment of MT's effectiveness for CP.

Based on our available findings, we suggest that MT be implemented in health/medical centers, specifically for patients with CNMP and cancer pain. The intervention should be conducted once per day, with a duration of 20 min. PMT using recorded music or AMT with live music can both be used. For PMT, patients should select their own music tracks and use earphones. In AMT, the therapist should use musical instruments during the therapy. The entire process should be guided by qualified music therapists and trained nurses. These findings provide a crucial foundation for the development of future clinical guidelines, aiming to optimize the application of music therapy in CP management. Future research should focus on developing operational guidelines for MT interventions in CP, outlining intervention processes and assessment standards, while expanding sample sizes and optimizing intervention designs. Additionally, the feasibility of home-based treatments should be explored. Comparative studies between individual and group MT should be conducted, along with an in-depth investigation into the mechanisms by which MT impacts CP and depression, as well as exploring its potential synergy with other therapies or medications. Developing countries should conduct more research, introducing innovative intervention models like AMT or diverse formats, including live music and vocal therapy, with long-term effectiveness evaluations to advance the widespread adoption of MT in CP treatment.

This study has the following advantages: First, we included only RCTs that used MT, excluding studies that combined MT with other therapies, and excluded high-risk studies [24,25,26,27,28] to ensure the quality of the included studies. Second, we included patients with all categories of CP and excluded studies that included patients with acute pain; thus, our results are relatively reliable. Third, through subgroup analyses, this study further investigated the effects of MT across Countries, Sample Sizes, Mean Ages, Settings, CP Categories, Intervention Equipment, Intervention Content, Intervention Durations, Music Selection, Qualifications, and Pain Assessment Tools, with no evidence of publication bias., and our results showed no publication bias. Fourth, our meta-analysis included quality of life as an outcome index for the first time to explore the relationship between MT and quality of life in patients with CP.

Limitations

This study has some limitations. First, although we used a comprehensive search strategy, only literature published in Chinese and English was retrieved, and studies published in other languages were not included. Second, although CP significantly reduced after MT intervention, only four studies reported follow-up. It is unclear whether MT has a long-term effect on pain in patients with CP. Third, Homogeneity cannot be guaranteed in the control group because the specific content of standard care was not reported and could not be compared. Furthermore, only certain categories of CP have been reported in the existing literature, and the effects on other specific CP categories are unclear, which may have led to bias in the results. Finally, only one study [19] reported changes in pain medication use, it showed that MT provided greater relief of cancer pain than analgesics alone, but it still should be more reliable evidence to analyze whether MT reduced pain medication use.

Conclusion

This study provides evidence that MT can reduce pain and depression in CP patients, though it has limited effects on anxiety and quality of life. Subgroup analysis reveals that MT is most effective when tailored to specific conditions, such as interventions in developed countries targeting CNMP or cancer pain, conducted in health centers, with patients selecting their own music, using instruments or earphones, and receiving therapy from trained professionals, ideally lasting 20 min. MT is a low-cost, non-invasive, and easily implemented therapy with significant clinical potential. Future research should develop standardized guidelines for MT implementation and evaluation to ensure consistency across studies. Additionally, studies should explore MT's long-term impact on pain, anxiety, quality of life, and its potential to reduce analgesic use, with a focus on its effects across different CP categories for reliable clinical evidence. High-quality, multicenter RCTs should be conducted in developing countries, explore cost-effective and culturally appropriate intervention models, ultimately advancing the global adoption of MT in CP management.