Overwhelmingly, cancer patients report sleepiness as well as fatigue as among the most disabling side effects they experienced following cancer and its treatment. Approximately 30% to 60% of all cancer patients report sleep disturbance as a significant problem,1,2 with long-term cancer survivors being 40% more likely than the normative population to experience distress.3 At time of treatment, distress is even more significant; of those sampled with the Hamilton Anxiety Depression Scale in a general oncology waiting room in Argentina, 74.9% surpassed the cutoff score for anxiety, depression, or both.4 In another study of US patients awaiting chemotherapy, depression and anxiety were prevalent, with 45% of those sampled endorsing sleep disturbance.5
Sleep is exquisitely sensitive to psychosocial challenge and medical compromise. Those with cancer are vulnerable to sleep disturbance from several forces. Cancer patients come into their illnesses with a level of psychiatric and medical comorbidities that are at least equivalent to those represented in the general population (and possibly more given the increased incidences of cancer associated with some lifestyle habits). It therefore stands to reason that manifestation of psychiatric illness, psychological vulnerabilities, and maladaptive coping would intensify with the added compromise of cancer and its treatments.
There is evidence that some patients grow with regard to psychosocial sophistication following cancer, a process termed benefit finding.3,6,7 However, patients who grow through adverse experience are likely not newly developing this capacity as a consequence of their cancer experience, but rather they are individuals who already have the disposition to turn adversity around and to use the challenge of the cancer experience to develop broader coping and perspective on the world and themselves.
Our task, then, in understanding the interface between cancer, psychiatric disturbance, and sleep is to break down each and develop possible directions for future strategies in treating sleep disturbance based on psychiatric issues faced by cancer patients. An additional task is to guide patients to feel more enabled and more realistically optimistic about their ability to modify symptoms.
The interface between cancer, psychiatry, and sleep is a tridirectional one. Each may adversely or beneficially affect the other. The two major sleep-related compromises that patients face in cancer are insomnia and airway-related sleep disorders. The latter, although less significantly associated with psychological causes than the former, has been shown to affect mood substantially. Another area of frequent sleep disturbance that deserves attention is circadian rhythm disturbance, which has recently been gaining investigative interest. Movement disorders such as periodic limb movement disorders (PLMD) and restless legs syndrome (RLS) are additional areas that affect cancer patients.
A major focus of this chapter is primary insomnia related to the diagnosis of cancer and its treatments. The International Classification of Sleep Disorders (ICSD-9)8 differentiates several forms of insomnia, the principal ones of which for our purposes include: ...