Influence of White Sound on Sleep Quality, Anxiety, and Depression in Patients with Schizophrenia

Abstract

Background:

Patients with schizophrenia frequently experience issues such as poor sleep quality, anxiety, and depression. White sound has been identified as a potential therapeutic strategy to enhance sleep quality and alleviate negative emotions. This study aimed to investigate the effectiveness of white sound in improving sleep quality, anxiety, and depression among patients with schizophrenia.

Materials and Methods:

This retrospective analysis included clinical data from 212 patients with schizophrenia divided into two groups based on their treatment approach. Group C (control, without white sound, n = 106) received standard pharmacological treatments, while group W (white sound, n = 106) was exposed to white sound (40–50 dB) for 2 hours nightly at 9:00 pm. All patients were assessed using the Pittsburgh Sleep Quality Index (PSQI), Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Positive and Negative Syndrome Scale (PANSS) before and after 12 weeks of intervention.

Results:

After 12 weeks, group W showed significant improvements in sleep latency, sleep efficiency, and overall PSQI scores compared to group C (P < 0.05). Furthermore, the HAMD and HAMA scores were significantly lower in group W (P < 0.05), indicating reduced levels of anxiety and depression. The negative symptoms score was significantly lower in group W (P < 0.05) after treatment.

Conclusion:

White sound shows promise in improving sleep quality, and alleviating anxiety and depression in patients with schizophrenia.

INTRODUCTION

Schizophrenia is a severe, chronic mental disorder, predominantly emerging in youth and early adulthood.[1,2] The etiology of schizophrenia is currently attributed to a complex interplay of genetic and environmental factors.[3,4]

Sleep disturbances are notably prevalent in patients with schizophrenia, and are closely linked to symptom development, mental status, and pharmacological treatments. Such disturbances can significantly impact the disorder’s progression and treatment efficacy.[5,6]

Patients with schizophrenia frequently experience varying levels of anxiety and depression, influenced by factors such as confusion, delusions, neurotransmitter imbalances, and abnormal brain functions.[7,8] Recent research has identified an association between schizophrenia, severe bipolar depression, and the degeneration of monoamine axons.[9]

White sound is characterized by a random signal that maintains a constant energy density across all frequencies within the human audible range. It provides a uniform volume and frequency, resulting in a continuous and soothing sound.[10] Recent studies suggest that white sound, acting as a “harmonious” therapeutic sound, can mask disruptive environmental noises during sleep, fostering a tranquil and conducive sleep environment for patients. This conducive setting is believed to enhance sleep quality, relieve mental stress, and improve mood. While white sound has been primarily studied in children with attention deficit hyperactivity disorder and newborns, mainly focusing on sleep parameters, there is limited research on its impact on negative emotions.[11,12] This study aimed to investigate the impact of white sound on sleep quality, anxiety, and depression in patients with schizophrenia.

STUDY METHODOLOGY AND PARTICIPANT SELECTION

Participants

This study was conducted in the Department of Psychology at the Third Hospital of Quzhou.

A retrospective analysis was conducted on clinical data from 212 patients with schizophrenia, divided into group W (white sound) and group C (control, without white sound), each comprising 106 patients. Group C was administered conventional medication, whereas group W received a combination of white sound therapy and standard medicines. Participants diagnosed with schizophrenia were subjected to this 12-week treatment regimen. Participants in group W and group C met specific inclusion and exclusion criteria:

Inclusion Criteria

• (1)Diagnosis of schizophrenia according to the International Classification of Diseases-10[13] criteria
• (2)Age range: 18 to 55 years (both inclusive)
• (3)Hemodynamically stable
• (4)Ability to read and understand Chinese

Exclusion Criteria

• (1)Organic brain disease or a history of alcohol addiction
• (2)History of drug addiction
• (3)Clinically significant concurrent medical illnesses
• (4)Presence of other mental disorders
• (5)Severe cognitive impairment
• (6)History of severe brain trauma
• (7)Pregnancy

Therapeutic Method

All participants from both study groups received conventional medications to maintain stable clinical symptoms. These included haloperidol (H33020585, Ningbo Dahongying Pharmaceutical Co Ltd, China), chlorpromazine (H44021428, Guangdong Bidi Pharmaceutical Co Ltd, China), clozapine (Jiangsu Nhwa Pharmaceutical Co Ltd, China), risperidone (H20050160, Jiangsu Nhwa Pharmaceutical Co Ltd, China), olanzapine (H20183500, Qilu Pharmaceutical Co Ltd, China), sulpiride (H32023126, Jiangsu Tisli Diyi Pharmaceutical Co Ltd, China), and aripiprazole (H20041506, Shanghai Sino-West Pharmaceutical Co Ltd, China). The prescribing physician made necessary dosage adjustments throughout the study.

Group W played a variety of white sounds, including the calm sound of rain, forest insects, birds in the mountains, and flowing water, using a white sound player at the bedside. The volume was controlled at 40 to 50 dB and adjusted according to individual hearing preferences to ensure patient comfort. Participants selected their preferred white sound and played it for 2 hours daily starting at 9 pm, over 12 weeks.

Assessments

The survey questionnaire includes Pittsburgh Sleep Quality Index (PSQI), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), and Positive and Negative Syndrome Scale (PANSS) for all participants.

Sleep Quality

The PSQI was utilized to assess the sleep quality of participants in both groups before the initiation of treatment and 12 weeks afterward. The PSQI comprises nine items, and each rated on a scale from 0 to 3, covering seven components: sleep quality (score for item 6), sleep time (score for items 2 and 5a), sleep latency (score for item 4), sleep efficiency (scores for items 1, 3, and 4), sleep disturbances (scores for items 5b to 5j), hypnotic drugs (score for item 7), and daytime dysfunction (scores for items 8 and 9), with a total possible score of 21. Higher scores indicate worse sleep quality.[14]

Anxiety and Depression

The HAMA and HAMD were used to evaluate anxiety and depression levels in the participants. The HAMA consists of 14 items, each scored from 0 to 4, with the overall score being the aggregate of all item scores. Scores <8 points indicate normal levels, 8 to 14 indicate possible anxiety, 15 to 21 suggest certain anxiety, 22 to 29 indicate obvious anxiety, and >29 points suggest severe anxiety. The HAMD includes 24 items, with 10 between 0 and 2 points, and 14 scored between 0 and 4 points. The total score is the sum of all items, where scores <8 are considered normal, 8 to 19 suggest possible depression, 20 to 35 indicate certain depression, and >35 indicate severe depression.[15,16]

Mental Condition

The PANSS was employed to evaluate the mental condition of the participants before and 12 weeks after treatment. It features three subscales: the positive symptom scale, the negative symptom scale, and the general psychopathological symptom scale, totaling 30 items. Each item is rated on a seven-level scoring scale, with the overall score being the aggregate of the three subscales. Higher scores denote more severe symptoms.[17]

Statistical Analysis

Patient data from both groups were imported into an Excel worksheet (Microsoft Corporation, Redmond, WA). Continuous variables were presented as mean ± standard deviation, and comparisons between group W and group C for quantitative variables were conducted using independent sample t-tests. Paired quantitative variables were analyzed with the paired t-tests. Categorical variables were expressed as percentages and analyzed using the Chi-square test. Statistical significance was set at a P-value of <0.05. Data were analyzed using SPSS 27.0 software (IBM, Armonk, New York, USA).

RESULTS

Demographic Details

The two groups had no significant differences in the demographic parameters (P > 0.05), as detailed in Table 1.

Table 1.

Comparison of Demographic Parameters between Group W and Group C.

Parameter	Group W*	Group C†	t/χ2	P-Value
Age (years)	39.42 ± 9.54	37.73 ± 9.75	1.276	0.204
Weight (kg)	68.71 ± 8.74	67.84 ± 9.81	0.682	0.496
Height (cm)	167.99 ± 8.78	167.11 ± 9.03	0.719	0.473
BMI (kg/m2)	24.36 ± 2.74	24.11 ± 3.04	0.629	0.530
Sex (men: women)	66:40	61:45	0.491	0.483
Course of disease (years)	15.87 ± 7.27	16.75 ± 7.75	0.853	0.395

BMI = body mass index. ^*Group W (white sound). ^† Group C (control, no white sound).

Pittsburgh Sleep Quality Index Scores

The two groups had no significant differences in the baseline PSQI scores (P > 0.05). At the 12-week evaluation, sleep latency, sleep efficiency, and total PSQI scores in group W were significantly lower than group C (P < 0.05), as detailed in Table 2.

Table 2.

Comparative Evaluation of Pittsburgh Sleep Quality Index Scores between Group W and Group C.

PSQI		Group W*	Group C†	t-Value	P-Value
Sleep latency	Baseline	1.94 ± 0.87	1.93 ± 0.84	0.085	0.932
	12 Weeks	0.76 ± 0.69	1.10 ± 0.75	3.435	0.001
Sleep quality	Baseline	1.38 ± 1.05	1.4 3 ± 1.15	0.331	0.741
	12 Weeks	1.00 ± 0.82	1.07 ± 0.91	0.588	0.557
Sleep efficiency	Baseline	1.56 ± 1.10	1.68 ± 1.16	0.773	0.440
	12 Weeks	0.62 ± 0.72	1.00 ± 0.80	3.635	<0.001
Sleep time	Baseline	1.32 ± 1.03	1.48 ± 1.13	1.077	0.283
	12 Weeks	0.95 ± 0.87	1.04 ± 0.87	0.753	0.452
Hypnotic drugs	Baseline	1.60 ± 1.14	1.66 ± 1.04	0.400	0.689
	12 Weeks	0.98 ± 0.87	1.05 ± 0.84	0.596	0.552
Sleep disturbances	Baseline	1.62 ± 1.09	1.58 ± 1.11	0.265	0.791
	12 Weeks	1.03 ± 0.80	1.04 ± 0.89	0.086	0.932
Daytime dysfunction	Baseline	1.50 ± 1.12	1.46 ± 1.03	0.271	0.787
	12 Weeks	0.80 ± 0.78	0.85 ± 0.80	0.461	0.645
Total score	Baseline	10.95 ± 2.78	11.25 ±2.80	0.783	0.435
	12 Weeks	6.16 ± 2.17	7.18 ± 2.10	3.478	0.001

PSQI = Pittsburgh Sleep Quality Index. ^*Group W (white sound). ^† Group C (control, no white sound).

Hamilton Anxiety Scale Scores

No significant differences were observed in the baseline HAMA scores between the two groups (P > 0.05). However, after 12 weeks of treatment, HAMA scores in group W were significantly lower than those in group C (P < 0.05), as shown in Table 3.

Table 3.

Comparison of Hamilton Anxiety Scale Scores between Group W and Group C.

HAMA		Group W*	Group C†	t-Value	P-Value
Total score	Baseline	19.20 ± 2.34	19.30 ± 2.42	0.318	0.751
	12 Weeks	9.64 ± 2.33	11.84 ± 2.19	7.074	<0.001

HAMA = Hamilton Anxiety Scale. ^*Group W (white sound). ^† Group C (control, no white sound).

Hamilton Depression Scale Scores

The two groups had no significant difference in baseline HAMD scores (P > 0.05). After 12 weeks of treatment, HAMD scores in group W were significantly lower than those in group C (P < 0.05), as depicted in Table 4.

Table 4.

Comparison of Hamilton Depression Scale Scores between Group W and Group C.

HAMD		Group W*	Group C†	t-value	P-value
Total score	Baseline	21.12±2.67	21.04±2.57	0.236	0.814
	12 weeks	10.21±2.14	12.80±2.38	8.351	<0.001

HAMD (Hamilton Depression Scale). * Group W (white sound). ^† Group C (control, no white sound).

Positive and Negative Syndrome Scale Scores

Baseline PANSS scores showed no significant difference between the two groups (P > 0.05). At 12 weeks of treatment, the scores for negative symptoms in group W were significantly lower than those in group C (P < 0.05), as shown in Table 5.

Table 5.

Comparative Analysis of Positive and Negative Syndrome Scale Scores between Group W and Group C.

PANSS		Group W*	Group C†	t-Value	P-Value
Positive symptoms	Baseline	17.59 ± 3.67	17.53 ± 3.81	0.117	0.907
	12 weeks	12.94 ± 2.32	12.58 ± 2.24	1.149	0.252
Negative symptoms	Baseline	14.89 ± 3.07	15.31 ± 3.05	0.999	0.319
	12 weeks	11.38 ± 2.11	12.20 ± 2.18	2.276	0.024
General psychopathological symptoms	Baseline	27.49 ± 3.69	26.73 ± 3.59	1.520	0.130
	12 weeks	21.80 ± 3.31	21.91 ± 3.70	0.228	0.820
Total score	Baseline	59.98 ± 5.43	59.58 ± 5.69	0.524	0.601
	12 weeks	46.13 ± 4.61	46.70 ± 4.68	0.893	0.373

PANSS = Positive and Negative Syndrome Scale. ^*Group W (white sound). ^†Group C (control, no white sound).

DISCUSSION

Sleep disorders frequently occur in patients with schizophrenia.[18,19,20,21] While conventional treatments can alleviate patients’ mental symptoms, improving sleep quality has not received adequate attention.

This study demonstrated that after 12 weeks of treatment, sleep latency, sleep efficiency, and total PSQI scores for group W were significantly lower than those for group C (P < 0.05). The effectiveness of white sound is attributed to its repetitive, monotonous frequency and consistent density spectrum, which can effectively mask other sounds, creating a shielding effect that filters out minor external noise variations and eliminates noise.[22] Furthermore, the continuous and soothing sound of white sound helps regulate physiological rhythms, facilitating a smooth transition between sleep and wakefulness, and promoting uninterrupted sleep. Moreover, natural sounds played in the white sound group helped alleviate the stress responses in patients, allowing them to enjoy natural sounds and improve sleep quality.

Similar findings were observed by Ebben et al.[23] in patients with sleep disorders, indicating that white sound improves sleep quality in noisy environments. Warjri et al.[24] discovered that playing white sound twice daily improved sleep quality in patients admitted to the ICU. Liao et al.’s[25] study on 103 premature infants in China showed that the white sound group had better sleep duration and efficiency than those in the silent sound group and a higher rate of newborn weight gain than the mother’s sound group. This study is the first to focus on patients with schizophrenia. Moreover, our research expanded the investigation to examine the impact of white sound on anxiety and depression, moving beyond a sole focus on its influence on sleep conditions, with a larger sample size than similar studies.

Patients with schizophrenia frequently manifest signs of diminished social function, disinterest, loneliness, and helplessness at the onset of the disorder. Although some individuals in the convalescent stage regain self-awareness, reintegration into society places significant physical and mental pressure on them, hindering their ability to assimilate into social groups and leading to negative emotions such as anxiety and depression. Furthermore, both the condition itself and the medications prescribed for its treatment can contribute to these adverse emotional states.

In this study, at the 12-week evaluation, the HAMA scores and HAMD scores for group W were significantly lower than those for group C (P < 0.05). This outcome suggests that white sound aids in calming emotions, relaxing the body and mind, and alleviating mental stress. Through appropriate white sound stimulation, a relaxation and sedative effect is produced, effectively easing the nervous tension in patients with schizophrenia, enhancing their sense of security, and improving their mood. Regarding anxiety reduction, Son et al.[26] discovered that playing white sound during the walking activities of older patients with mild dementia could reduce anxiety and fear of falling without impacting their walking pace, aligning with the conclusions of this study. To date, no research has explicitly reported on white sound’s effectiveness in mitigating depression. Numerous studies have linked decreased dopamine levels with stochastic resonance identified as crucial in dopamine signaling. Noise must be continuous to induce stochastic resonance effects and to exhibit high energy levels uniformly across all frequencies, akin to white or pink sound. It is hypothesized that in conditions of low dopamine, transmitting white sound into the nervous system via sensory pathways may activate the dopamine system and modulate neural responses.

This study has limitations, including the restricted age range of patients (18–55 years) and variability in individual treatment plans, which are not uniformly consistent. Furthermore, treatment medication may affect sleep quality. Extending the treatment to encompass all age groups and differentiating among patients with varied treatment approaches could offer a more comprehensive evaluation of white sound’s impact on schizophrenia.

CONCLUSION

This study has effectively demonstrated that white sound can improve sleep quality, and alleviate anxiety and depression in patients with schizophrenia. However, white sound should be used as an adjunct to pharmacotherapy, and cannot be fully substituted for drug therapy.

Financial support and sponsorship

Nil.

Conflict of Interest

The authors declare no conflict of interest.

Funding Statement

Funding: Not applicable.