The Effect of Color Therapy on Anxiety in Chemotherapy Patients Attending the Oncology Department: A Randomized Clinical Trial

Abstract

Introduction

Anxiety is a prevalent and distressing symptom experienced by cancer patients undergoing chemotherapy, which can adversely affect treatment adherence and quality of life.

Objective

This study aimed to evaluate the effectiveness of color therapy in reducing anxiety in patients undergoing chemotherapy.

Methods

A randomized clinical trial was conducted involving 190 patients with oncology diagnoses who were admitted to the chemotherapy department. Participants were randomly assigned to either the intervention group, which was exposed to a blue therapeutic room, or the control group, which was placed in a standard hospital setting. Anxiety levels were assessed using the Beck Anxiety Inventory before the intervention and again after a 20-minute exposure. Data were analyzed using SPSS Version 25.

Results

The intervention group demonstrated a significant reduction in anxiety scores, decreasing from 57.70 ± 10.14 to 50.03 ± 8.49 (p < .05), while the control group showed no significant change (56.48 ± 5.09–55.83 ± 9.15).

Conclusion

Color therapy effectively reduces anxiety in chemotherapy patients as a cost-effective and noninvasive complementary method. To implement these findings, oncology units should integrate structured color-based interventions into routine care. Training healthcare staff and conducting pilot studies are essential to ensure proper application and assess feasibility.

Introduction

Cancer, as defined by the National Cancer Institute (NIH), is a pathological condition characterized by uncontrolled proliferation and systemic dissemination of abnormal cells (Xia et al., 2022). Globally, cancer is the second leading cause of death, following cardiovascular diseases (Siegel et al., 2023). In Iran, it ranks third, after traffic accidents and cardiovascular diseases (Roshandel et al., 2021). Approximately 9 million new cases are diagnosed annually worldwide, with nearly 60% occurring in low- and middle-income countries (Siegel et al., 2023). The Global Cancer Observatory projects that the worldwide cancer burden will reach 28.4 million cases by 2040 (Xia et al., 2022).

Epidemiological data indicate that approximately two in five Canadians will be diagnosed with cancer during their lifetime (Roshandel et al., 2021). Due to demographic shifts and population aging, cancer incidence (excluding nonmelanoma skin cancers) is projected to increase by 35%, from 84,800 cases in 2012 to 129,700 cases by 2025 (Siegel et al., 2023). In Iran, breast, stomach, colorectal, and esophageal cancers were most prevalent in 2012, with projections suggesting increases in multiple cancer types, including leukemia, by 2025 (Chhikara & Parang, 2023).

Cancer treatment encompasses diverse modalities, including surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy, hematopoietic stem cell transplantation, and hormonal therapy (Di Nardo et al., 2022; Li et al., 2024). Chemotherapy remains a cornerstone, employing cytotoxic agents to inhibit cancer cell proliferation or induce apoptosis (Mohammadi et al., 2021). However, conventional chemotherapy affects not only malignant cells but also healthy rapidly dividing cells, leading to fatigue, alopecia, nausea, immunosuppression, cognitive impairments, and mood disturbances (Grusdat et al., 2022; Ikhile et al., 2024).

Anxiety associated with both anticipation and experience of chemotherapy side effects is highly prevalent, impairing psychological well-being, with multiphase screening identifying up to 70% of patients affected (Grusdat et al., 2022; Oei et al., 2024). Consequently, establishing supportive and calming environments is critical for mitigating psychological distress and enhancing treatment adherence and outcomes (Debela et al., 2021).

Color, a vital environmental factor, exerts profound psychological effects: red increases arousal and energy, whereas blue promotes relaxation, anxiety reduction, and psychological comfort (Saragih, 2024). Strategic implementation of color schemes in clinical settings may alleviate anxiety and enhance patient well-being (Gupta, 2021). Despite extensive research in color psychology, empirical evidence regarding therapeutic effects in cancer patients remains limited (Jakobsson Støre & Jakobsson, 2022; Mirzaei & Movahed, 2020).

For example, Mohammadi and Habibi (2023) examined color preferences, reporting that mothers preferred desaturated soft colors, nurses favored calming cool hues, and children responded to vibrant yet gentle colors (Mohammadi & Habibi, 2023). These findings underscore the importance of designing therapeutic healthcare environments using appropriate color palettes (Jonauskaite et al., 2020). Gupta (2021) reported that color therapy's effectiveness varies with cultural and personal differences, highlighting psychosocial factors and the necessity for personalized anxiety interventions (Gupta, 2021). Accordingly, psychological, cultural, and individual factors should be considered in color-based interventions (Elhawary et al., 2024). While color therapy may benefit some individuals, its effectiveness depends on multiple psychological, cultural, and personal variables (Safitri & Marjohan, 2023). Rigorous research, particularly among chemotherapy patients, is essential to clarify its potential role as an adjunctive strategy for anxiety reduction (Zhou et al., 2023), with personalization likely enhancing therapeutic efficacy (Nazari et al., 2020).

Colors directly influence neuropsychological processes, promoting stress reduction and mental relaxation (Safitri & Marjohan, 2023). However, research on color therapy's effects on chemotherapy-related anxiety remains limited and inconclusive (Oei et al., 2024). Given its noninvasive, safe, and cost-effective nature, further investigation is warranted (Turturro & Drake, 2022). This study aims to evaluate color therapy's effectiveness in reducing anxiety among hospitalized chemotherapy patients, offering insights for supportive oncology environments and improving psychological well-being.

Literature Review

Color therapy has emerged as a promising complementary intervention for alleviating anxiety in cancer patients (Tamamm et al., 2022). Exposure to specific calming colors, particularly blue and green, reduces psychological stress and promotes relaxation in clinical settings (Zhou et al., 2023). Its psychological effects are especially relevant during high-anxiety situations such as chemotherapy (Putri et al., 2025). Integrating color therapy with complementary practices, including mindfulness and therapeutic coloring activities, further enhances mental calmness and overall quality of life (Samuel et al., 2022; Takemura et al., 2021). Designing healing environments with soft, natural color palettes also supports psychological well-being (Gürcan & Atay Turan, 2021).

Mandala art therapy, involving coloring symmetrical patterns, promotes mindfulness, meditative states, and emotional regulation by fostering focused attention and providing calming sensory stimulation (Akbulak & Can, 2023; Gürcan & Atay Turan, 2021; Khademi et al., 2021). While sharing similarities with general color therapy, Mandala therapy represents a distinct modality with unique psychological mechanisms (Jakobsson Støre & Jakobsson, 2022).

Despite these promising findings, research specifically examining color therapy for anxiety management in oncology patients remains limited (Naser et al., 2021; Saragih, 2024). This gap highlights the need for further rigorous studies to validate and optimize color therapy within cancer care (Debela et al., 2021; Grusdat et al., 2022). Anxiety in chemotherapy patients arises from multiple factors, including treatment side effects, disease progression, and disruption of daily life, significantly affecting emotional well-being and treatment adherence. Given this complexity, this study explores how personalized color therapy may reduce anxiety by addressing patients’ specific psychological needs.

Methodology

Design

This randomized controlled trial was conducted between 2021 and 2022. The study procedures adhered strictly to the CONSORT guidelines, ensuring methodological rigor and transparency (Merkow et al., 2021).

Setting and Participants

The study population included all cancer patients visiting the hospital's oncology department. Participants were recruited through convenience sampling. Eligible patients were those undergoing chemotherapy, hospitalized for more than 6 hr for chemotherapy sessions, and willing to partake in the study. Patients who were unable to attend weekly sessions or had anxiety scores outside the predefined range were excluded. In total, 300 patients were screened, and after applying the inclusion and exclusion criteria, 190 patients were enrolled (Figure 1).

Figure 1.

CONSORT Flowchart.

Sampling and Sample Size

The sample size was calculated based on a two-tailed hypothesis by comparing a quantitative characteristic (anxiety level) between two independent groups, considering a 95% confidence interval (α = 0.05) and 90% statistical power (β = 0.10). Parameters for the calculation were derived from a similar study conducted by Kırca et al. (2024), which investigated the effects of Mandala coloring on anxiety and quality of life in postmenopausal women (Kırca et al., 2024). According to the formula, 170 participants per group were necessary. Considering a potential 10% attrition rate, the final sample size was adjusted to 190 participants, with an equal distribution between the intervention and control groups.

Ethical Considerations

The study was approved by the relevant Research Ethics Committee, with the ethical clearance code duly documented. All participants were fully informed of the study objectives, procedures, and their rights, including voluntary participation and the ability to withdraw at any time without consequence. Written informed consent was obtained from each participant. Confidentiality was ensured by using unique codes for questionnaires, and all data were utilized exclusively for research purposes. Measures were implemented to safeguard participant anonymity and privacy throughout the study.

Randomization and Allocation Concealment

Participants were randomly assigned to either the intervention group or the control group using a computerized random number generator, ensuring that assignment to groups was fully random and reproducible. An independent statistician, who had no role in participant recruitment or outcome assessment, managed the randomization process to prevent any potential bias. To maintain allocation concealment, the randomization sequence was stored in sequentially numbered, opaque, sealed envelopes, which were opened only at the time of participant enrollment by a study coordinator following the predetermined order. This procedure ensured that both participants and the enrolling staff were unaware of upcoming assignments, minimizing the risk of selection bias and preserving the integrity of the randomization process.

Given the nature of the intervention, participants and care providers could not be blinded to group assignments due to the distinct environmental and procedural differences between intervention and control conditions. However, outcome assessors remained blinded to participant allocation, ensuring that the assessment of study outcomes was unbiased. The limitation regarding participant and provider blinding was explicitly acknowledged and accounted for in the study design and analysis.

Outcomes

Primary outcome: Anxiety severity assessed using the Beck Anxiety Inventory (BAI) immediately before and immediately following the 20-minute color therapy intervention.

Secondary outcomes: Not specified.

Data Collection Procedures

Data collection took place in the oncology department waiting area. Upon arrival, participants completed a demographic questionnaire and the BAI to assess baseline anxiety levels. After this initial assessment, participants were escorted to their assigned rooms—either blue-themed or standard. Following 20 min of exposure, the BAI was re-administered to evaluate changes in anxiety.

Instruments

Two principal instruments were employed for data collection:

Demographic Information Form: This instrument captured participants’ sociodemographic and clinical characteristics, including age, gender, marital status, cancer type, educational attainment, number of offspring, and duration since cancer diagnosis.

Beck Anxiety Inventory (BAI): The BAI is a 21-item self-administered questionnaire designed to quantify the severity of anxiety symptoms in adolescent and adult populations (do Nascimento et al., 2023). Each item is rated on a 4-point Likert scale ranging from 0 (not at all) to 3 (severe), yielding a cumulative score between 0 and 63. Anxiety severity is stratified into minimal (0–7), mild (8–15), moderate (16–25), and severe (26–63) categories. The BAI exhibits robust psychometric properties, with validity coefficients ranging from 0.72 to 0.74 and reliability indices (Cronbach's alpha) ranging from 0.82 to 0.90. The present study corroborated these psychometric benchmarks, reporting validity at 0.74 and reliability at 0.82.

Following the initial assessment, participants were randomly assigned to either the intervention or control group. The intervention group was escorted to specially prepared blue-themed rooms designed to deliver environmental color therapy. These rooms incorporated calming blue tones via LED lighting, bed linens, curtains, and decorative items such as blue-themed wall art and artificial flowers. Psychological literature supports blue's calming effects, including reductions in heart rate and blood pressure, thereby promoting emotional stability. Participants remained in this therapeutic environment for 20 min without staff interaction. Immediately after the session, the BAI was re-administered to assess postintervention anxiety. In contrast, the control group was placed in standard oncology rooms with neutral wall colors (white or off-white), conventional fluorescent lighting, and no environmental modifications. Control participants spent the same duration (20 min) in these rooms. Routine nursing care—such as chemotherapy preparation, vital sign monitoring, and side effect management—was provided to both groups by hospital staff independently of the research team, ensuring consistency across conditions. The only distinguishing factor between groups was the environmental color exposure, allowing for isolation of the intervention effect.

Data Analysis

Data were analyzed using SPSS Version 25. Within-group pre- and postintervention anxiety differences were assessed via paired t-tests, while between-group comparisons employed ANOVA. Baseline demographic and clinical equivalence was examined using chi-square, Fisher's exact, and Yates’ correction tests (p < .05).

Results

The findings related to demographic information and disease characteristics of the study participants were analyzed using the chi-square test, the Mann-Whitney test, and the independent t-test. The results revealed that there were no statistically significant differences between the intervention and control groups about these variables, indicating that the two groups were homogeneous (p > .05) (see Table 1).

Table 1.

Distribution of Absolute and Relative Frequencies of Study Participants for Personal and Disease Characteristics Variables in the Intervention and Control Groups.

Variables		Intervention group (%)	Control group (%)	Test statistic	p-value	Test used
Gender	Male	46 (46.9%)	52 (53.1%)	0.75	.468	Chi-square
	Female	49 (53.1%)	43 (46.9%)
Marital status	Single	22 (41.5%)	31 (58.5%)	2.12	.196	Chi-square
	Married	73 (53.3%)	64 (46.7%)
Education level	Illiterate	16 (51.6%)	15 (48.4%)	5.07	.288	Chi-square
	Below diploma	24 (39.3%)	37 (60.7%)
	High school/diploma	22 (53.7%)	19 (46.3%)
	Bachelor's degree	23 (54.8%)	19 (45.2%)
	Above bachelor's	10 (66.7%)	5 (33.3%)
Cancer type	Colon	16 (45.7%)	19 (54.3%)	11.37	.233	Chi-square
	Breast	19 (50%)	19 (50%)
	Lymphoma	10 (47.6%)	11 (52.4%)
	Lung	5 (27.8%)	13 (72.2%)
	Stomach	10 (62.5%)	6 (37.5%)
	Uterus and ovaries	7 (35%)	13 (65%)
	Blood	11 (68.8%)	5 (31.3%)
	Other	17 (64.5%)	9 (34.5%)
Age (mean ± SD)		50.75 ± 7.96	50.90 ± 7.92	−0.12	.38	Independent t-test
Number of children (mean ± SD)		2.21 ± 1.57	2.75 ± 1.58	0.87	.38	Independent t-test
Duration of diagnosis (mean rank)		97.64	93.36	−0.543	.587	Mann-Whitney

p-values < .05 were considered statistically significant.

Descriptive results of pretest and posttest anxiety scores in the intervention and control groups are presented. According to the findings of the independent t-test, no statistically significant difference was observed between the mean anxiety scores of the intervention and control groups in the pretest (p > .05). The results of this test showed that there was a statistically significant difference between the mean anxiety scores of the intervention and control groups in the posttest (p < .05). The findings of the paired t-test indicated that there was a significant change in the mean anxiety score in the intervention group (p < .05). Additionally, the results of this test showed that in the control group, no significant change was observed in the mean anxiety score (p > .05) (see Table 2).

Table 2.

Mean and Standard Deviation of Anxiety Scale by Groups, Before and After Intervention.

Variable	Time	Before intervention	After intervention	Statistical index
		Mean ± SD	Mean ± SD
Anxiety	Intervention	57.70 ± 10.14	50.03 ± 8.49	p-value = .001, t = 6/877
	Control	56.48 ± 5.09	55.83 ± 9.15	p-value = .406, t = 0/836
Statistical index		p-value = .048, t = 0/297	p-value = .001, t = 0/001

p-values < .05 were considered statistically significant.

Before performing analysis of covariance (ANCOVA) to examine the effect of the color therapy intervention on anxiety, Levene's test was conducted to verify the assumption of homogeneity of variances. The test showed no significant difference in anxiety score variances between the intervention and control groups after the treatment, F(1, 188) = 0.312, p = .577. This result confirms that the data meet the necessary assumptions for ANCOVA, ensuring that the subsequent analysis will produce valid and reliable results. Ensuring homogeneity of variances is crucial for the validity of ANCOVA, as it guarantees that group variances are comparable, allowing a fair assessment of the treatment effect (see Table 3).

Table 3.

Results of Homogeneity of Variances for Anxiety in Cancer Patients.

Stage	Variable	df1	df2	Test statistic	p-value
After intervention	Anxiety	1	188	0/312	0/577

p-values < .05 were considered statistically significant.

To evaluate the effectiveness of color therapy on reducing anxiety in chemotherapy patients, ANCOVA was conducted, controlling for baseline anxiety scores. The analysis showed a statistically significant difference in posttest anxiety scores between the intervention and control groups, F(1, 188) = 28.157, p = .001. The effect size (η² = 0.131) indicates that 13.1% of the variance in anxiety reduction is attributable to the color therapy intervention. These results demonstrate a moderate and clinically meaningful effect, supporting color therapy as an effective complementary approach for alleviating anxiety in chemotherapy patients (see Table 4).

Table 4.

Results of Analysis of Covariance for Comparing the Mean Anxiety Scores Between the Intervention and Control Groups.

Source of variance	Dependent variable	Sum of squares	Degrees of freedom	Mean squares	f	p-value	Effect size
Group	Anxiety	1882.873	1	1882.873	28/157	0/001	0/131

p-values < .05 were considered statistically significant.

Discussion

The primary objective of this study was to rigorously evaluate the efficacy of color therapy as a complementary intervention for reducing anxiety in cancer patients undergoing chemotherapy. This population is known to experience elevated levels of psychological distress, which can negatively impact treatment adherence, overall quality of life, and clinical outcomes (Safitri & Marjohan, 2023). Given the invasive nature of chemotherapy and the uncertainty regarding prognosis and side effects, there is an urgent need for accessible, noninvasive, and cost-effective interventions to alleviate this psychological burden (Di Nardo et al., 2022).

The findings reveal a statistically and clinically significant reduction in anxiety among patients exposed to blue-themed environmental color therapy. Baseline anxiety scores were comparable between intervention and control groups (p > .05), confirming homogeneity. Postintervention, anxiety significantly decreased in the intervention group (p < .05) with no change in controls. ANCOVA controlling for baseline scores confirmed the effect, F(1, 188) = 28.157, p = .001; η² = 0.131, indicating that 13.1% of the variance in anxiety reduction was attributable to color therapy. This moderate effect suggests meaningful improvements in psychological well-being, quality of life, and treatment adherence. Future studies should examine the effects on specific anxiety components.

From a mechanistic standpoint, color serves as a potent environmental stimulus capable of modulating emotional and cognitive processes, thereby shaping patient experiences during medical treatments (Saragih, 2024). Physiological exposure to specific hues may influence autonomic nervous system regulation and neurotransmitter pathways associated with mood and anxiety, while concurrently diverting attention from anxiety-provoking stimuli (Turturro & Drake, 2022). Consistent with prior literature, cool colors such as blue and green have been linked to anxiolytic effects in clinical contexts (Mohammadi & Habibi, 2023; Okyay et al., 2025; Turturro & Drake, 2022). For example, Shahrbabaki et al. (2025) reported that children in the mandala coloring intervention group experienced a significant reduction in preoperative anxiety compared to their baseline levels, suggesting that both environmental exposure to colors and active engagement with coloring activities may exert calming effects in clinical contexts (Shahrbabaki et al., 2025).

Beyond passive exposure to color, interactive approaches such as Mandala art therapy—which engages patients in coloring symmetrical patterns—have demonstrated promising therapeutic outcomes by fostering mindfulness and meditative states. This engagement promotes focused attention and sensory stimulation, which can disrupt maladaptive thought patterns and enhance emotional regulation (Jakobsson Støre & Jakobsson, 2022). Empirical evidence from Sreetha et al. (2021) shows that regular participation in Mandala coloring significantly alleviated depressive symptoms in elderly populations, suggesting that active color-based therapies may offer deeper psychological benefits compared to ambient color exposure alone (Sreetha et al., 2021).

In the context of healthcare environmental design, color plays a vital role. Samuel et al. (2022) found that color therapy reduced symptoms of anxiety and depression in patients with generalized anxiety disorder, recommending the use of calming hues such as blue and purple in clinical units (Samuel et al., 2022). Similarly, Mirzaei and Movahed (2020) observed that hospital environments featuring blue, green, and white color schemes were associated with reduced stress and expedited recovery (Mirzaei & Movahed, 2020). However, some studies have reported mixed results influenced by cultural and individual differences. For instance, Mohammadi and Habibi (2023) observed significant variability in color preferences among pediatric patients, their mothers, and nursing staff, underscoring the importance of customizing color interventions to the unique needs and perceptions of different populations (Mohammadi & Habibi, 2023). Separately, Nazari et al. (2020) found that purple combined with natural sunlight effectively reduced anxiety levels in ICU patients, whereas exposure to dark blue and green did not produce significant anxiety reduction, possibly due to negative emotional associations with these colors in certain individuals (Nazari et al., 2020)). These findings highlight the critical importance of considering patient preferences, cultural context, and environmental factors when applying color therapy. Thoughtful and tailored use of color in clinical settings can optimize psychological outcomes and enhance patient satisfaction.

In summary, this study provides evidence supporting color therapy as a low-risk, noninvasive, and cost-effective complementary strategy for mitigating anxiety in chemotherapy patients. The moderate effect size and clinical relevance underscore its potential utility within holistic oncology care (Takemura et al., 2021). Future research should explore combined passive and active color-based interventions, long-term effects, and the influence of cultural and individual differences to refine and personalize therapeutic approaches. Optimizing color therapy protocols could significantly enhance psychological well-being and treatment experiences for cancer patients worldwide.

Strengths and Limitations

This study possesses several important strengths. The randomized clinical trial design enhances methodological rigor and internal validity of the findings. By specifically targeting anxiety reduction in chemotherapy patients, the study addresses a critical psychological need in a vulnerable population. The use of color therapy as a nonpharmacological, noninvasive, and cost-effective intervention supports emotional well-being without adding medication-related burdens. Conducting the research within real-world clinical settings further increases external validity and practical applicability in routine oncology care. The intervention's adaptability to other hospital departments strengthens its potential scalability. Nevertheless, the study faced certain limitations. Some participants experienced physical discomfort, fatigue, or emotional distress related to treatment, which challenged questionnaire completion. Participants were allowed extended time or multiple sessions to complete assessments, minimizing missing data and enhancing dataset reliability. It is important to note that data collection occurred over three years ago. While this may limit immediacy, the psychological needs and proposed intervention remain relevant in current oncology settings. Anxiety in chemotherapy patients continues to be a significant concern, and exploring nonpharmacological strategies like color therapy retains value. Future studies should employ updated methodologies, recent clinical data, and larger, more diverse samples to validate and expand upon these findings.

Implications for Practice

The findings support integrating color therapy, particularly calming blue tones, into clinical settings to reduce anxiety among chemotherapy patients. Healthcare administrators should prioritize incorporating blue-themed elements—such as wall paint, LED lighting, bedding, curtains, and décor—in oncology wards to create soothing environments that enhance psychological well-being. Hospitals can operationalize these findings by developing protocols for selecting and implementing blue schemes, training staff on their benefits, and regularly collecting patient feedback to optimize interventions. Given its cost-effective and noninvasive nature, color therapy can extend to other high-anxiety areas, including surgical, intensive care, and pediatric units. Policymakers should establish standardized guidelines for environmental color use, considering patient demographics and clinical needs. Interdisciplinary collaboration among planners, interior designers, clinicians, and mental health professionals is essential to design comprehensive anxiety management plans. Ongoing research should refine protocols by examining different colors, exposure durations, and diverse patient populations to implement evidence-based strategies that improve comfort, adherence, and clinical outcomes.

Conclusion

The study results indicate that color therapy, particularly blue, significantly reduces anxiety in chemotherapy patients. The intervention group demonstrated decreased mean anxiety scores after exposure to a blue environment, highlighting its psychological benefits as a nonpharmacological intervention. Implementing calming blue schemes in oncology units—through lighting, wall paint, and furniture—can support psychological well-being, enhance the therapeutic atmosphere, and improve the overall care experience. These findings advocate integrating color therapy into psychosocial care strategies.