Major depressive disorder (MDD) or major depression is the most commonly diagnosed form of depression [1] and was ranked by the World Health Organization as the third leading cause of disease burden in 2018, with projections placing it first by 2030 [2]. MDD is defined by a persistently low mood, loss of interest or pleasure (anhedonia), recurrent suicidal thoughts, and a range of physical and cognitive symptoms—including sleep disturbance, changes in appetite and weight, fatigue, psychomotor agitation or retardation, feelings of worthlessness, and difficulty concentrating [3-5]. According to the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition; DSM-5), diagnosis requires at least 5 of these symptoms lasting a minimum of 2 weeks [6].

The global incidence of MDD has steadily increased over the past 3 decades [7], with a sharp 27.6% rise in 2020 linked to the COVID-19 pandemic [8]. The most recent Global Burden of Disease (GBD) study estimated that 229 million people worldwide were affected by MDD in 2021, with the highest prevalence rate in the United States (4527 cases per 100,000 population; 15 million cases) and Europe (3771 cases per 100,000 population; 32 million cases) [7,9]. Globally, MDD is more prevalent in women, with a female-to-male ratio of approximately 1.6, as reported in the most recent GBD study, rising to 1.9 in the United States and Europe [7].

MDD severely impacts quality of life (QoL) not only due to its core symptoms but also because of functional limitations, social disruption, and comorbidities [3,10]. The severity of depressive symptoms directly correlates with greater QoL impairment [11-13]. Among these symptoms, sleep disturbances, especially insomnia, are among the most common, affecting around 60% of people with depression [14,15]. Insomnia symptoms are frequently reported as the main complaint [16], further deteriorating QoL by worsening energy levels and mood, and overall functioning [15,17]. Sleep disturbances in MDD are also linked to more severe symptoms—persistent depression, higher relapse risk, poorer response to traditional depression treatment, and increased risk of suicidality [18-26]. Insomnia symptoms often persist despite antidepressant treatment [27] and after remission of depressive symptoms, making individuals with MDD experiencing insomnia symptoms (MDDIS) particularly difficult to treat [28,29].

Though the literature suggests MDD and sleep disturbances are associated [16,20,30], the persistence and clinical consequences of insomnia symptoms highlight a critical need for interventions to address sleep disorders in MDDIS to improve patients’ outcomes. Despite extensive research [31,32], recent data capturing patient-reported outcomes on insomnia symptoms in MDD remain limited, particularly regarding how patients perceive its impact on their lives and how this knowledge can guide the development of more effective care strategies.

To address the absence of data on patients’ perspectives regarding the impact of insomnia symptoms on patients’ lives and treatment needs, we collected current patient-reported data on insomnia symptoms among individuals with MDDIS in the United States and Europe. The primary objective of this descriptive study was to assess the burden of insomnia symptoms and patient-reported QoL in this population. We also sought to understand how patients perceive the relationship between their sleep disturbances and depression, how they perceive their current MDDIS treatments, and if they discuss their insomnia symptoms with a clinician or another member of their care team.

In this paper, we present findings from this observational study that provides insights into the lived experience of MDDIS, focusing on how insomnia symptoms shape their daily functioning and well-being.

This was a noninterventional, observational, and cross-sectional web-based study targeting patients who self-reported a diagnosis of depression and symptoms of insomnia.

Eligible participants were adults (≥18 years) residing in the United States, or in 1 of 5 European countries (EU5; France, Germany, Italy, Spain, or the United Kingdom), who self-reported a health care professional diagnosis of MDD, self-reported insomnia symptoms, and who provided informed consent. Participants who did not meet the inclusion criteria or who did not fully complete the questionnaire were excluded from the analysis. No medical records, prescriptions, or physician confirmation were requested as part of the study.

The target sample size was 1250 participants: 500 from the United States and 750 from EU5.

Participants were recruited through Carenity (ELSE CARE), an online community launched in 2011, where both patients and caregivers share experiences, access health-related information, and participate in online research studies. Carenity members were invited to participate by email. Recruitment also involved online campaigns (Facebook; Meta Platforms Inc. and Google; Alphabet Inc.). No incentives were provided for participation in the study.

Data were collected between October 2022 and February 2023.

The study protocol was approved by the Western Institutional Review Board–Copernicus Group (WCG IRB; approval number 20223963). All participants provided electronic informed consent prior to completing the study.

The study population included all participants who met the study selection criteria and completed the questionnaire. Descriptive statistics were used to characterize the study population and summarize study responses. Quantitative data are reported using mean and its 95% CI and qualitative data are reported as frequencies and percentages. Results are presented separately by region of residence (United States or EU5). Descriptive subgroup analyses were conducted according to current depressive episode status, depression severity, and other relevant clinical characteristics. Differences in the distribution of categorical variables between subgroups were assessed using Pearson chi-square tests or Fisher exact test. All statistical tests were 2-sided, and a P value <.05 was considered statistically significant.

All data management and statistical analysis were performed using R software (version 4.1.2; R Core Team).

Recruitment targets were met in both regions (United States and EU5), resulting in a total of 1250 participants: 500 in the United States and 750 in EU5. Details of participant disposition are shown in Figure 1. Demographic and clinical characteristics of the study population are detailed in Table 1.

In both the United States and EU5, the majority of participants were cisgender women (United States: 363/500, 72%, and EU5: 637/750, 85%). A total of 12% (62/500) of US participants identified as transgender or nonbinary, compared to 3% (21/750) in the EU5 sample. Mean age at inclusion was similar across regions (United States: 48.1, 95% CI 46.5‐49.7 years; EU5: 47.5, 95% CI 46.5‐48.6 years) and most participants were diagnosed with MDD in their mid-thirties. In both regions, the majority of participants reported receiving their MDD diagnosis from a psychiatrist, with 79% (127/161) in Italy, 72% (111/154) in Germany, 68% (95/140) in Spain, 59% (98/167) in France, and 28% (36/128) in the United Kingdom (Table S1 in Multimedia Appendix 1).

Comorbid mental health conditions were prevalent. The majority of participants from both regions reported at least one additional condition, most commonly generalized anxiety disorder, chronic anxiety or stress, posttraumatic stress disorder, social anxiety disorder, and panic disorder. At the time of the study, 86% (429/500) of United States and 87% (655/750) of EU5 participants were experiencing depressive symptoms or were in an active depressive episode, which had started less than a year earlier for over half of the participants. Among those not in an active episode, most had experienced one within the past year.

When asked how they think insomnia is related to their depression, the majority of participants, 88% (439/500) in the United States and 85% (639/750) in the EU5, believed both conditions are linked. In both regions, 58% (United States: 290/500; EU5: 437/750) considered insomnia symptoms to be part of their depression, while 33% (164/500; United States) and 23% (171/750; EU5) believed their depression was a cause of their insomnia symptoms. Around 20% (United States: 95/500; EU5: 150/750) in each region felt that insomnia symptoms contributed to their depression (Figure 7).

This cross-sectional study provides patient-reported evidence for the burden of insomnia symptoms among individuals with MDD. Overall, insomnia symptoms were commonly reported despite treatment use, with moderate to severe symptoms more commonly reported among participants with more severe depression and those currently experiencing a depressive episode. Participants also described a substantial impact of insomnia symptoms on daily functioning, emotional well-being, cognitive functioning, and productivity, expressing low satisfaction with the perceived effectiveness of current treatments for sleep symptoms and a desire for additional therapeutic options. Collectively, these findings highlight the considerable patient-reported burden associated with insomnia symptoms and suggest that persistent sleep difficulties remain an important aspect of the patient experience.

This study shows that insomnia symptoms remain highly prevalent among patients with MDD, even among individuals receiving treatment. These findings are consistent with previous epidemiological studies showing that sleep disturbance is a common feature of depression and that insomnia symptoms may persist despite improvement in depressive symptoms, increasing the risk of relapse and recurrence [14,15,30,31]. Furthermore, the results suggest a link between insomnia severity and depression severity; participants with more severe depressive symptoms were more likely to report greater insomnia severity, in line with previous literature showing that short sleep and insomnia are independently associated with increased depression severity and symptom frequency [39,40]. These findings support the importance of considering sleep disturbance as a clinically relevant component of the overall burden of MDD, in particular among those with more severe depression.

Beyond their high prevalence, insomnia symptoms were perceived as having a substantial impact on multiple aspects of daily functioning. Participants reported impairments affecting emotional well-being, cognitive functioning, or work productivity, consistent with previous studies demonstrating that people with both depression and sleep problems experience daytime symptoms such as poor concentration and fatigue, and that insomnia symptoms have a strong negative impact on QoL and psychological distress [15,17].

Participants’ perceptions further illustrate the complexity of the relationship between insomnia symptoms and depression. Although insomnia is recognized as a core symptom of MDD [14], some participants still do not perceive their sleep difficulties as being part of their depression. This finding may reflect limited awareness of the relationship between these conditions and supports the need to provide patients with information regarding the coexistence of mood and sleep symptoms [14,16,30].

Treatment use was high, despite the prevalence of insomnia symptoms. The majority of participants reported dissatisfaction with the perceived effectiveness of antidepressants for improving sleep symptoms and expressed interest in alternative therapeutic options addressing both depression and sleep. Previous literature has observed that more than half of patients perceived antidepressants as insufficient for improving sleep and seek additional support [15]. However, this study did not assess treatment adherence, treatment duration, clinical appropriateness, or treatment resistance. Therefore, these findings should be interpreted as reflecting patients’ perceptions of persistent sleep difficulties despite treatment rather than evidence of inadequate clinical management.

Despite the well-established literature demonstrating an association between depression and insomnia symptoms [14,16,30-32,41], this association is not adequately reflected in current treatment practices. Although most participants reported discussing their sleep difficulties with a clinician or another member of their care team, over one-third indicated that no treatment suggestions were provided. As the study did not capture the reasons underlying these interactions, alternative explanations, including patient preferences, clinical judgment, or treatment prioritization, cannot be excluded. Nevertheless, these findings suggest a potential communication or care gap that warrants further investigation.

A major strength of this study is its large multinational sample recruited through an online patient community, allowing the collection of patient-reported experiences from individuals with MDD across 6 countries [42]. The use of validated instruments (PHQ-9 and ISI) ensured standardized assessment of depression and insomnia severity, while the study-specific questionnaire provided valuable insights into patients’ treatment experiences, perceptions, and unmet needs. Compared with previous studies that primarily focused on the economic burden and health care resource use associated with insomnia symptoms in MDD [31,32], this study offers a broader understanding of the patient experience and highlights aspects of disease burden that are not routinely captured in clinical practice.

Several limitations should nevertheless be acknowledged. Recruitment through an online platform may have introduced selection bias by excluding individuals without internet access or those less familiar with digital tools, and by preferentially including patients who are more engaged in managing their condition. In addition, the sample was predominantly composed of cisgender women, which may limit the generalizability of the findings to the broader MDD population [7]. The observed differences in the proportion of participants identifying as transgender or nonbinary between the United States and the EU5 may also reflect cultural and societal differences in the willingness to disclose sex identity.

All data were self-reported, introducing the possibility of recall and reporting bias. In particular, the diagnosis of MDD was based on participant self-report and was not independently confirmed through medical records or health care professionals, which may have resulted in diagnostic misclassification. Furthermore, information regarding treatment adherence, treatment duration, treatment optimization, clinician rationale for treatment selection, and treatment resistance was not collected, limiting the interpretation of participants’ reported treatment experiences. Sleep duration, a factor known to influence the relationship between insomnia and depression, was also not assessed and may have acted as a confounder. Finally, the cross-sectional design precludes any conclusions regarding temporal or causal relationships between insomnia symptoms and depression severity.

Future longitudinal studies integrating both patient- and clinician-reported outcomes are warranted to better characterize the relationship between insomnia symptoms and the onset, course, and treatment response of MDD. Such studies should also investigate behavioral and educational aspects of insomnia management, including patients’ understanding of the relationship between sleep and depression, as well as strategies that promote adaptive coping and improve long-term outcomes.

Given the well-established association between depression and insomnia symptoms reported in the literature [38], our findings further emphasize the importance of considering sleep symptoms during the clinical assessment of patients with MDD. Although this study cannot determine the appropriateness of current treatment strategies, the persistence of patient-reported sleep difficulties and the expressed need for additional therapeutic options suggest that insomnia symptoms remain an important component of patient care deserving continued clinical attention.

This multinational patient study highlights the substantial burden associated with insomnia symptoms among individuals with MDD. Participants reported an impact of insomnia symptoms on daily functioning, emotional well-being, and productivity. More severe depression was accompanied by a greater proportion of participants with moderate or severe insomnia symptoms, and dissatisfaction with current treatment options was widespread. Around two-thirds of participants also expressed a desire for additional treatment options. Although the cross-sectional design and patient-reported nature of the data preclude conclusions regarding causality or the appropriateness of current clinical management, these findings suggest that insomnia symptoms remain an important component of the patient experience in MDD and identify a potential care gap that warrants further investigation.