The Chicken and/or the Egg?

This chapter covers the bidirectional relationship between depression and insomnia. Patients with insomnia are more likely to develop depression; the prevalence of depression in people with comorbid insomnia is almost 10 times greater than in those without insomnia. Conversely, depression itself has sleep disturbance as a symptom 80% of the time. Treatment of comorbid insomnia and depression should aim at treating both conditions. While cognitive-behavioral therapy for insomnia (CBT-i) should always be considered in the treatment of chronic insomnia, instances may arise when medications are required. Sedative–hypnotics derive from a wide variety of classes of medications and may need to be used in conjunction with antidepressants in the depressed insomniac.