INSOMNIA
COMORBID WITH MAJOR DEPRESSIVE DISORDER

Management Approaches

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Amit Chopra, MD, DFAPA.

 

INTRODUCTION

Insomnia is defined as a predominant dissatisfaction with sleep quantity or quality, associated with one or more specific symptoms including difficulty initiating sleep, difficulty maintaining sleep, and early morning awakening with inability to return to sleep.

 

Based on DSM-5 criteria, the sleep difficulty should occur at least 3 times per week for 3 months or more, despite adequate opportunity for sleep for establishing a diagnosis of insomnia disorder. Insomnia is the most common sleep complaint with trouble initiating sleep (initial insomnia), disrupted sleep (middle insomnia), early morning awakenings (terminal insomnia), and/or non-restorative sleep during acute major depressive episodes. Evidence suggests that insomnia correlates strongly with a significantly increased risk of developing depression. Given substantial evidence that each condition predisposes towards the development of others, a bi-directional link between insomnia and depression exists. Not only does insomnia increase the risk of depression, but it also contributes to poor depression treatment outcomes. The re-emergence of insomnia in patients with remitted depression can predict the recurrence of a new depressive episode. Finally, insomnia has been increasingly recognised as a risk factor for death by suicide independent of depression severity. Because of these reasons, it is imperative to comprehensively assess and treat insomnia in patients with major depression to improve remission rates, prevent relapse of depressive illness, and reduce suicide risk.

Assessment

 Insomnia Severity Index is a validated self-report screening tool to assess insomnia severity, patient satisfaction with sleep quality, daytime impairment, and overall distress caused by sleep dysfunction. It is crucial to screen for primary sleep disorders that are frequently comorbid with major depression such as obstructive sleep apnoea, restless legs syndrome, and circadian rhythm sleep disorders while formulating a treatment plan for the management of insomnia. Comorbid medical issues, medication side effects, lifestyle factors, and substance use patterns contributing to worsening of insomnia need to be addressed for optimal treatment outcomes. Polysomnography studies are not generally recommended for evaluation of insomnia unless primary sleep disorders, such as obstructive sleep apnoea, are suspected clinically. Studies have associated polysomnography findings such as reduced slow-wave sleep (SWS), decreased rapid eye movement (REM) sleep latency, and increased rapid eye movement (REM) sleep density in patients with major depressive disorder.

Polysomnography Sleep Changes in Major Depression

Reduced slow-wave sleep (SWS)

Decreased rapid eye movement (REM) sleep latency

Increased rapid eye movement (REM) sleep density

In terms of assessment,

Behavioural Treatments

Evidence suggests that cognitive-behavioural therapy for insomnia (CBT-I), now considered as a first-line psychotherapeutic intervention for management of primary insomnia, can be an effective treatment modality for insomnia comorbid with major depression. CBT-I is comprised of key techniques such as stimulus control, sleep restriction, cognitive restructuring, and relaxation techniques. Individuals with both depression and insomnia may have difficulties adhering to cognitive-behavioural therapy for insomnia treatments, particularly those with severely reduced total sleep time (less than 3.65 hours of sleep) who are at greatest risk for early termination of CBT-I. To improve adherence to CBT-I and target depressive symptomatology, it is recommended to incorporate elements of both CBT-I and cognitive behavioural therapy for depression (CBT-D) to achieve optimal outcomes for insomnia.

Pharmacotherapies

In terms of pharmacotherapy, we can use sedating antidepressants either as monotherapy (if tolerated at full therapeutic doses) or as an adjunct to first-line antidepressant treatments.  Sedating antidepressants including mirtazapine, trazodone, and tricyclic antidepressants (TCAs) are often used to treat insomnia; however, this practice has not yet been systematically substantiated and needs further investigation. Doxepin (3-6 mg) is the only sedating antidepressant that is FDA-approved for the management of insomnia.  Clinicians prescribing adjunct sedating antidepressants should carefully assess the long-term need of prescribing such medications periodically to minimise the risk of over-sedation and anticholinergic side effects in the long-term. There is promising evidence supporting the safety and efficacy of benzodiazepine receptor agonists such as zolpidem and eszopiclone for treatment of insomnia with standard first-line antidepressants for major depression. Benzodiazepine receptor agonists have lesser addiction potential as compared to benzodiazepines; however, clinicians need to be cautious in patients with comorbid substance use disorders while prescribing these medications. Amongst second-generation antipsychotics, quetiapine seems to have the most evidence in improving insomnia, although clinicians need to do a thorough risk-benefit analysis and monitor the patients for the emergence of adverse effects including daytime somnolence, akathisia, extrapyramidal symptoms, weight gain, dyslipidaemia, and hyperglycaemia. More research is needed for novel interventions used for treatment-resistant depression, such as ketamine and repetitive transcranial magnetic stimulation (rTMS), which may hold promise to improve sleep outcomes in patients with major depression.

Summary

In summary, insomnia is a commonly prevalent and difficult-to-treat condition that is associated with increased depression severity, poor treatment outcomes, and increased risk of depressive relapse, suicidal ideations, and even suicide. Medications and behavioural approaches, alone or in combination, may prove to be effective in treating sleep disturbances associated with major depression; however, more research is warranted in this area to develop optimal and novel management strategies. Cognitive-behavioural therapy for insomnia (CBT-I), a promising treatment for the management of insomnia comorbid with major depression, needs wider implementation and more research to establish its efficacy in reducing suicide risk in patients with major depression.

 

Guest Author

Amit Chopra, MD, DFAPA 

Psychiatrist and Sleep Specialist, 

Associate Professor of Psychiatry, 

Medical Director, Centre for Psychiatric Neuromodulation, 

Medical Director, Centre for Treatment-resistant Depression, 

Allegheny Health Network, 

Pittsburgh, Pennsylvania, USA

Book

Management of Sleep Disorders in Psychiatry 1st Edition, Kindle Edition