Introduction

Insomnia disorder, which refers to the symptoms of not getting normal sleep, is a common disease with an increasing prevalence worldwide [1–6]. Transient episodes of short-term insomnia can occur extensively, resulting in chronic insomnia, which currently affects 30–50% of the adult population [7]. Therefore, it is necessary to manage the disease burden through appropriate nationwide management.

Treatment guidelines in several countries, including the United States, Europe, and Korea, recommend non-pharmacological treatment for insomnia, such as cognitive behavioral therapy, as the primary [8–14], as various clinical studies have shown their effectiveness in improving insomnia [15]. However, it is not practiced because it is time-consuming and expensive, and there is a lack of experts who can provide this treatment [16].

For individuals whose symptoms are difficult to treat with non-pharmacological treatments or whose condition does not improve after the treatment, prescribing hypnotics may be considered. However, hypnotics carry the risk of abuse, dependence, falls, and delirium. In Korea, concerns have been raised regarding the excessive use of sleeping pills [17], benzodiazepines, antipsychotics, and antidepressants [18].

This study aimed to confirm the initial treatments offered to patients diagnosed with insomnia disorder, specifically focusing on the proportion of patients who received non-pharmacological treatments. As the prevalence of insomnia disorder in Korea is gradually increasing [19], it is important to understand the treatment status to lay the foundation for designing clinical guidelines for patients with insomnia disorder. Therefore, we investigated the non-pharmacological treatment status in patients with insomnia disorder (ICD-CODE: G47) between 2002 and 2019 using data from the National Health Insurance Service (NHIS).

Methods

Results

Trend in patients with insomnia disorder

The number of people diagnosed with insomnia disorder per year continued to increase during the observation period from 7,937 in 2002–46,451 in 2019 (Table 1). The ratio of insomnia disorder to all patients increased from 1.3% in 2002 to 3.2% in 2019, and the average number of outpatient visits by patients with insomnia disorder increased over time (Fig 1).

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Table 1. General information of patient who diagnosis insomnia disorder (N = 518,119).

https://doi.org/10.1371/journal.pone.0334142.t001

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Fig 1. Annual incidence of insomnia disorder (ICD-CODE: G47) Bar: rate of insomnia disorder relative to all patients; Line: average number of outpatient visits for patients with insomnia disorder.

https://doi.org/10.1371/journal.pone.0334142.g001

Treatment at first diagnosis of insomnia disorder

Table 2 shows the distribution of treatment modalities received at the time of first diagnosis of insomnia disorder. Percentages represent the relative proportion of each treatment type among all treatments provided at the first diagnosis. Non-pharmacological treatments were prescribed to approximately 0.1% of the patients. The proportion of prescribed medications at the first diagnosis tended to decrease, whereas the proportion of counseling initially tended to increase. Anesthesia and imaging were excluded from the interpretation as they were not considered as a treatment for insomnia disorder and seemed to be because of other complications.

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Table 2. Treatment at first diagnosis of insomnia disorder (%).

https://doi.org/10.1371/journal.pone.0334142.t002

Fig 2 shows the distribution of non-pharmacological treatments administered during the first diagnosis. Approximately 0.01% of patients received non-pharmacological treatment from the first diagnosis. Fig 3 presents the mean interval by year of initial diagnosis, demonstrating a decreasing trend over time.

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Fig 2. Distribution of non-pharmacological treatment related to insomnia disorder (2002–2019).

https://doi.org/10.1371/journal.pone.0334142.g002

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Fig 3. Mean interval from initial diagnosis to initiation of non-pharmacological treatment by year.

The green bars indicate the mean interval from the initial diagnosis of insomnia disorder to the initiation of non-pharmacological treatment. The blue bars represent the year-specific number of patients who initiated non-pharmacological treatment after an initial diagnosis without it. The black bars denote the standard deviation (SD).

https://doi.org/10.1371/journal.pone.0334142.g003

Table 3 shows the detailed treatment status of patients who received non-pharmacological treatment at the first diagnosis of insomnia disorder. A total of 88 non-pharmacological treatments were reported, with individual supportive psychotherapy accounting for the largest proportion. Patients who did not receive non-pharmacological treatment at the first diagnosis but eventually received non-pharmacological treatment were most likely to receive individual supportive psychotherapy and often received short personal psychotherapy within 10 minutes (Table 4).

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Table 3. Detailed treatment status of people who received non- pharmacological treatment at first diagnosis.

https://doi.org/10.1371/journal.pone.0334142.t003

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Table 4. Detailed treatment status of patients who did not receive non-pharmacological treatment at first diagnosis but received it later.

https://doi.org/10.1371/journal.pone.0334142.t004

An additional chi-square analysis comparing patients who received non-pharmacological treatment at the first diagnosis, those who received it later, and those who never received it showed consistent demographic patterns: employed insurance holders, women, non-metropolitan residents, and higher-income patients accounted for the largest proportions in all groups (all p < 0.001) (S1 Table).

Discussion

Our analysis showed that less than 0.1% of patients received non-pharmacological treatment at the initial visit.

We observed that the proportion of patients receiving non-pharmacological treatments for insomnia was relatively low, and most patients did not receive non-pharmacological treatments even at first diagnosis. Contrary to the recommendations of various clinical guidelines for insomnia disorder, it has been confirmed that non-pharmacological treatments are not properly used in Korea. This could be because of various reasons, such as compensation for non-pharmacological treatment, time, cost, and the medical environment. Except for consultations, drugs and injections accounted for the largest proportion of the first treatment, and this phenomenon is similar in many places worldwide. Drugs such as benzodiazepines are the most commonly used treatments in the United States and were used by approximately 6–10% of adults as of 2010 [21]. In the UK, there was a study on the increased use of sleeping pills by patients with insomnia [1].

While pharmacological treatment can be an effective and easy way to address insomnia disorder, it is not a cure-all and may be associated with dependence and abuse with long-term use. Various studies have shown that combining medication and non-medication treatments can effectively improve sleep; therefore, it is crucial to provide appropriate non-pharmacological treatments [22–25]. As awareness of non-pharmacological treatment improves among physicians and patients, non-pharmacological treatments will be offered earlier, as suggested by the guidelines. This improvement in therapeutic approach is expected to have a positive impact on the treatment of insomnia disorder in the future.

On a positive note, the number of patients who did not receive non-pharmacological treatment at the initial diagnosis but later received it continued to increase over time. This increase is clinically meaningful, as earlier initiation of non-pharmacological treatment can enhance long-term outcomes and reduce the limitations of pharmacological therapy alone. The Ministry of Health and Welfare of Korea included cognitive behavioral therapy in its National Health Insurance list when it reorganized the health insurance system to further revitalize non-pharmacological treatment in 2018. Media reports have stated that this has increased the number of hospitals providing psychiatric care, making it more accessible to patients.

Moreover, various services for patients with insomnia disorders have recently been developed to provide non-pharmacological treatment using digital technology. Several studies have been conducted to verify the effectiveness of digital healthcare technologies for improving insomnia disorder [26–28]. The advantage of digital technologies is that they can overcome time and space constraints, which means that patients can use them to receive medical care without visiting a hospital. In many countries, digital healthcare services related to insomnia disorder are institutionalized within the healthcare system, even to the point of being reimbursed. Digital healthcare-based non-pharmacological treatments for insomnia disorder are expected to increase access to care for these patients.

This study has several limitations. First, insomnia disorder was defined using only the ICD-10 code G47, because the NHIS sample cohort database classifies psychiatric diagnostic codes such as F51 as sensitive information and does not provide them to researchers. In 2013, 35,003 patients were identified using only the G47 code. However, a previous nationwide study that included both G47 and F51 codes reported 43,961 patients during the same period, leading to a discrepancy of 8,958 cases [29]. This difference likely reflects the masking of F-code diagnoses in the NHIS datasets due to their classification as sensitive conditions. Consequently, the findings may be subject to selection bias, and caution is warranted when generalizing these results to the broader insomnia population.

Second, these findings should be interpreted in the context of broader demographic dynamics. The observed increase in patient numbers may, at least in part, reflect the effects of population aging and shifts in population structure. In addition, this study did not examine demographic factors that may underlie the observed decrease in medication use and increase in counseling. Future research with expanded datasets, including psychiatric F-codes, will be needed to investigate these trends in greater depth. Furthermore, because the observation period ended in 2019, patients first diagnosed in 2019 may have initiated non-pharmacological treatment after 2020 and were therefore not captured in this study. This limitation may have introduced bias in estimating the mean interval for the most recent cohorts, potentially leading to either underestimation or overestimation.

Third, there was no information on non-payment drug treatments in the health insurance data; therefore, details could not be considered owing to the data limitation. Finally, although this study describes various mixtures measured from the data used, the possibility of residual mixtures cannot be completely ruled out. However, despite these limitations, this study is unique in that it is the first in Korea to investigate prescriptions at the time of first diagnosis in patients with insomnia disorder. The results of this study are particularly noteworthy because they present the basis for desirable policy proposals in the future through a practical analysis of the contents of the guidelines for insomnia disorder.

This study explored the treatment preferences of Korean doctors for patients with insomnia disorders. At the time of initial diagnosis of insomnia disorder, there were few non-pharmacological treatments. However, patients who did not receive non-pharmacological treatment at the time of initial, the number of those who later received such treatment showed an increasing trend over time, which is noteworthy considering the importance of continuous management of insomnia disorder.

Supporting information