There is a two way connection between depression and sleep problems. Disturbances in one’s biological clock (circadian rhythm) may cause a neurobiological disorder (an illness of the nervous system) which in turn can be demonstrated as depressive symptoms; on the other hand, mood decline can affect the biological clock and cause insomnia and circadian rhythm sleep disorders 1 .
Depression, affecting more than 350 million people globally, is a mood disorder identified by low mood and/or lack of interest in activities previously found to be enjoyable. Depression affects the way a person eats, sleeps, feels and thinks.
Evidence suggests that people with insomnia have a ten-fold risk of developing depression compared with those who sleep well. Around 60%–80% of patients with major depression suffer from sleep disorders, especially insomnia 2 3 . Depressed individuals may suffer from a variety of insomnia symptoms, including difficulty of falling asleep (sleep onset insomnia), difficulty staying asleep (sleep maintenance insomnia), non-refreshing sleep, and daytime sleepiness. However, research suggests that the risk of developing depression is highest among people with both sleep onset and sleep maintenance insomnia. Patients with psychiatric diagnoses, including depression, post-traumatic stress disorder (PTSD), schizophrenia and comorbid sleep disturbances were significantly more likely to report suicidal behavior 4 . Sleep problems and depression may also share risk factors and biological features, while the two conditions may respond to some of the same treatment strategies.
The best treatment for insomnia in patients with depression is a combination of lifestyle changes, behavioural strategies, psychotherapy, and drugs if necessary.
Cognitive behavioral therapy (CBT): CBT refers to a variety of behavioural strategies used to correct harmful or negative thought patterns and behaviours that can cause or worsen insomnia. People with insomnia tend to become preoccupied with not falling asleep, while cognitive behavioural techniques help them change their negative expectations and try to build confidence that they can have a good night’s sleep. Studies show that CBT may represent a useful clinical strategy for improving sleep quality in patients with depression and insomnia 5 .
Lifestyle changes: Insomniacs should also adopt healthy habits and rituals that promote a good night’s sleep such as fixed bed and wake times, keeping the bedroom dark and free of distractions like computer or television, relaxing before going to bed, maintaining a comfortable sleeping environment, avoiding daytime naps and avoiding consumption of caffeine, alcohol, and nicotine within 3 hours before sleep. Practicing positive thoughts, meditation, deep breathing exercises, and progressive muscle relaxation can counter anxiety and racing thoughts. Regularly exercising (but not within 3 hours before going to sleep) can also help people fall asleep faster, spend more time in deep sleep, and to wake up less often during the night.
Medication options: In many cases non-drug intervention is not enough. Given the bi-directional relationship between depression and insomnia, a medication that improves sleep quality may be a rational approach for improving the medical condition of psychiatric patients, and in particular improve the quality of life of depressive subjects 6 7 . A variety of medications are available to treat sleep problems, however, it is important to notice that many anti-depressants have untoward adverse effects on sleep, particularly causing or worsening insomnia, daytime sleepiness or sedation, and increasing the risk to develop Alzheimer’s disease.
The most commonly prescribed anti-depressants are the SSRIs (selective serotonin reuptake inhibitors), however some of them may cause or worsen insomnia.
Ramelteon showed improvement in sleep parameters (shorter latency, increased total sleep time and reduction of daytime sleepiness) as well as a reduction in anxiety symptoms, but studies have also shown it may also worsen depression 8 .
Agomelatine 9 10 improved sleep quality and reduced waking after sleep-onset in depressive patients 11 . However, due to the risk of common liver enzymes elevation and rare serious liver reactions, routine laboratory monitoring of liver function is recommended periodically throughout treatment 12 .
Controlled-release melatonin (2.5–10 mg) as an add-on to standard antidepressant treatment demonstrated improvement in sleep compared to placebo but had no effect on the rate of improvement in depression symptoms 13 .