We do know that psychological disorders are comorbid (occur together) with sleep disorders. There is debate as to whether the lack of sleep causes (for example) depression or if, instead, depression creates a brain/behavior pattern that disrupts sleep.
In either case, an individual in pain will have difficulty with sleep onset and sleep maintenance. And an individual who has not slept will cope more poorly with pain. Some patients cannot sleep when taking narcotic analgesia. They become drowsy, but their sleep architecture (the pattern of their sleep) is disrupted. Further, their sleep hygiene (how they handle the process of falling asleep) is often maladaptive since they may worry about a forthcoming procedure, the inability to meet the emotional and financial needs of their family, and the ability to make decisions, plan events and concentrate on what they are being told.
Many of the symptoms associated with sleep deprivation, both onset and maintenance,are also found in depressed and anxious patients. While not surprising, it does create a concern for what we are treating as the primary problem. Are we to target the pain with the expectancy that sleep and mood will not be impacted?
Arguably, treating pain without addressing depression and sleep may be a risky approach. If there is no investigation as to how the patient is sleeping (information often best obtained from a family member), we do not know if the patient is primarily depressed. S/he may have the classic sleep pattern (early awakening) of depressed patients, or is s/he not sleeping due to pain emerging in the middle of the night, and s/he is not, in fact, depressed.
Even patients who are depressed may either not acknowledge (or know) that this is true or are resistant to admitting depression since it impugns the image of strength they wish to convey. It does not appear that questions regarding sleep and/or depression will be asked when examining patients in acute or chronic pain although we have sufficient research to know that pain, sleep and depression and closely related emotionally and physically.