There are many new findings in the area of comorbid insomnia. Almost 50% of all cases of chronic insomnia are due to a mental disorder, with depressive illness explaining the majority of cases related to mental disorder (Slide 1). Other common causes of comorbid, or secondary, insomnia include chronic respiratory disease such as asthma and chronic obstructive pulmonary disease, chronic pain, degenerative neurological disease, and some medications such as glucocorticoids and serotonin reuptake inhibitors. A general principle of management of insomnia related to mental or medical disorders is that the principal disorder must be fully treated as part of the insomnia treatment plan. If there is an offending medication, it must be discontinued if possible.