High prevalence of major depression in US sleep clinics: the need for routine depression screening in sleep services

Abstract

Depression screening is not part of routine clinical practice in US sleep clinics. Our study aimed to report the prevalence of depression among individuals referred to US sleep clinics. According to our findings, approximately 21% of patients had depression, with about 4% reporting severe symptoms, 9% had frequent death and/or self-harming thoughts, and 61% were taking antidepressants. Our results highlighted a considerable risk of prevalent depression in sleep clinics and supported the limited existing data on this topic. Our study advocates for the need for routine depression screening in sleep services to reduce the detrimental consequences of a delayed depression diagnosis and the risk of a worse prognosis for both depression and sleep–wake disorders.

Citation:

Daccò S, Caldirola D, Grassi M, Alciati A, Perna G, Defillo A. High prevalence of major depression in US sleep clinics: the need for routine depression screening in sleep services. J Clin Sleep Med. 2023;19(4):835–836.

INTRODUCTION

Clinical practice and the available scientific literature indicate that major depression disorder (MDD) and sleep–wake disorders have a bidirectional relationship.

Sleep disturbances are one of the most common symptoms of MDD and are included in its diagnostic criteria. Around 90% of the individuals with MDD report disturbed sleep quality and about 66% experience insomnia, including difficulties in initiating or maintaining sleep and early morning awakenings.¹ Residual sleep disturbances can also be an important symptom of inadequate MDD treatment, representing a risk factor for the recurrence of depression and suicidal thoughts and behaviors.²

Clinicians sometimes fail to recognize depression and might inappropriately refer patients to sleep clinics (SCs) for polysomnography to investigate the origin of sleep disturbances. Therefore, some authors have previously advocated the importance of routine depression screening in SCs.^3,4 However, current guidelines recommend psychological screening only for some sleep–wake disorders, such as insomnia, but not as part of routine clinical practice. Moreover, the lack of a systematic depression screening increases the risk of missing the diagnosis and adversely affects treatment choices and depression outcomes. The duration of untreated depression and the delay in antidepressant treatment have been correlated with worse outcomes,² and the inappropriate use of hypnotics and sedatives to treat sleep disturbances in depressed patients has been associated with an increased incidence of depression exacerbations and recurrence.⁵

The failure to recognize and treat early depression can also be detrimental to the prognosis of sleep–wake disorders. Comorbidity between depression and sleep–wake disorders is frequent in general and psychiatric populations. Among the limited and heterogeneous studies in SCs, depression is overrepresented in patients with different sleep–wake disorders when compared with the 8.4% observed in the US general population.⁶ Among patients with sleep–wake disorders, depressive symptoms have been found in up to 63% of patients using self-rating questionnaires and MDD has been reported in 20–30% of patients by performing psychiatric interviews.^3,7 Researchers have also reported similar rates of MDD diagnosed by performing psychiatric interviews among individuals with restless legs syndrome⁸ and narcolepsy.⁹ It is conceivable that untreated comorbid depression in these individuals maintains mechanisms such as inflammation and autonomic hyperarousal shared by sleep–wake disorders,¹ thereby negatively affecting their course.

Previous studies and international recommendations indicate the need to rectify the lack of routine depression screening in SCs.^3,4 We, therefore, aimed to expand the limited clinical data on the prevalence of depression in SCs, herein reporting these rates in a preliminary sample of 288 adults participating in our ongoing multicenter study involving 13 SCs around the United States. Our investigation aims to collect data for the development of a polysomnography-based algorithm capable of screening individuals who may currently have depression.

To maximize the specificity of identifying a current major depressive episode (MDE), we used the Patient Health Questionnaire, 9 items (PHQ-9) and scored it according to the algorithm based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition criteria (pooled sensitivity, 0.61; pooled specificity, 0.95).¹⁰

Our preliminary sample included participants (51% females, mean age 46.6 ± 14.8 years) with different sleep–wake disorders, as reported in their medical history, encompassing sleep-related breathing disorders (53%), insomnia (25%), restless legs syndrome (8%), narcolepsy (2%), rapid eye movement sleep behavior disorder (2%), and mixed sleep-related complaints (10%). Approximately 21% of patients had current PHQ-based MDE, with about 4% reporting severe symptoms (ie, PHQ-9 ≥ 20). Moreover, according to item 9 of the PHQ-9 (“Thoughts that you would be better off dead or of hurting yourself in some way”), 9% of patients with current MDE reported to have had those thoughts more than half the days in the last 2 weeks and 31% during several days, whereas none of those without MDE had those thoughts for more than half the days and only 2% for several days.

Notably, 61% of those with current MDE according to the PHQ-9 were taking antidepressants. Despite the lack of information concerning treatment doses and durations, the finding that some participants receiving antidepressants may still have possible depression suggests that screening in SCs could help to identify those who respond poorly to their pharmacotherapy and require clinical reassessment, monitoring, or therapeutic regimen changes.

In our study, the lack of clinician-administered psychiatric interviews is one of the crucial limitations that may affect the true prevalence of MDD. However, our results highlight the considerable risk of prevalent depression among individuals referred to SCs, supporting the limited existing data on this topic and confirming the need for routine depression screening in sleep services. This would reduce the risk of diagnostic and treatment errors and would improve therapeutic outcomes. Finally, implementing depression screening in clinical practice would also adhere to the accreditation requirements for sleep centers suggesting questionnaires or other screening assessments be included in patients’ medical records, which would represent a high-standard quality procedure toward good clinical practice in SCs.

DISCLOSURE STATEMENT

The manuscript has been seen and approved by all authors. Work for this study was performed at the Research and Development Department, Medibio Limited, United States HQ, Savage, MN 55378 and Department of Biomedical Sciences, Humanitas University, Milan, Italy. The authors report no conflicts of interest.