Treating Insomnia Disorder in the Context of Medical and Psychiatric Comorbidities

Insomnia is a commoncondition. It is estimated that approximately 30% of the population experiences some symptom of insomnia, and approximately 5% to 15% of these individuals are likely tomeet criteria for an insomniadisorder.1 Traditionally, insomnia was considered as either a primary disorder or secondary to another medical or psychiatric condition. During the past 2 decades, multiple lines of evidence have converged to support the proposition that insomnia, regardless of concurrent medical and/or psychiatric illness, is an independent disorder and should be treated accordingly.2 Partially in response, insomnia is now formally classified in the Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) as a separate disorder, and thediagnosisof insomnia secondary toanother condition was removed. Numerous studies have shown that targeted treatment for insomnia iseffective in thecontextofother conditions. The success of cognitivebehavioral therapy for insomnia (CBT-I)with secondaryor comorbid insomnia strongly suggests that, although insomniamaybe precipitated by psychiatric and/or medical illness, it is likely perpetuated by the same factors that are responsible for primary (chronic) insomnia.2 The application of CBT-I in patients with comorbid insomnia also had one significant and unexpected outcome: treatment gains were evident for the so-called parent disorder. For example, CBT-I in patients with depression led to 29% lower depression ratings vs medication alone.3 Given that numerous studies have found that CBT-I produces significant treatment outcomes in insomnia comorbid with such disorders as depression, chronic pain, and cancer (andoftenwithoutcomes that equal or exceed thenormswith uncomplicated insomnia), the time seems ripe to take stock of such findings within the framework of a proper metaanalysis. The investigation in this issueof JAMAInternalMedicine byWu and colleagues4 does precisely this. Cognitive-behavioral therapy for insomnia generally includes several components, such as sleep restriction therapy (aligningsleepopportunitywithsleepability tomaximizesleep efficiency), stimulus control therapy (maximizing the stimulus value of the bed andbedroom for sleep), sleephygiene (alleviatingobviousbarriers to sleep), cognitive therapy (addressingnighttime ruminations,worries, and fears), andsometimes relaxation interventions (reducingphysiologic arousal).5 Prior meta-analyses6 have shown that CBT-I is an efficacious treatment for reducing sleep latency, wake time after sleep onset, and earlymorning awakenings, aswell as increasing sleep efficiency. Furthermore, comparative meta-analyses7 have shown that CBT-I performs at least as well as pharmacotherapy or even slightly better in the short term, with superior results in the long term. Based on these and other findings, CBT-I has been adopted as a recommended first-line treatment for insomnia by the American Academy of Sleep Medicine. ThestudybyWuandcolleagues4examinedavailable clinical trials that evaluated CBT-I for insomnia in the context of other conditions. Studies were found that examined insomnia treatment in the context of substance abuse, renal disease, chronicpain, cancer,depression,posttraumatic stressdisorder,andotherconditions.Overall, this studyfoundthatCBT-I was associatedwith an increased likelihoodof remission from insomnia (odds ratio, 3.28; 95%CI, 2.30-4.68;P < .001). In addition, positive findingswere seen for improvements in sleep efficiencyandoverall sleepquality. Positive findingswere also seen for thecomorbidcondition ingeneral, such thatCBT-I improved noninsomnia outcomes as well. There was a significant interaction: effects on psychiatric comorbid conditions weremore robust thanwere effects for nonpsychiatric comorbidities. Themeta-analysis showed thatnotonlywasCBT-I effective in the faceof comorbid conditions, but theeffectswere relatively large (although slightly smaller thanmight be seen in primary insomnia). The studyhada few limitations that suggest directions for future research. First, the meta-analysis focused on remission and did not summarize outcomes with respect to treatment response. Second, the study couldhaveplacedmore focus on the benefits of CBT-I for the comorbid condition. As noted above, there are several studies in the literature showing that treatment of comorbid insomnia not only improves the insomnia but also improves severity and/or tolerance of symptoms of the comorbid condition (eg, produces treatRelated article page 1461 Research Original Investigation Cognitive Behavioral Therapy for Comorbid Insomnia