The nature of stable insomnia phenotypes

Psychomotor Vigilance Impairment During Total Sleep Deprivation Is Exacerbated in Sleep-Onset Insomnia

PURPOSE

Individuals with primary insomnia frequently report cognitive impairment as a next-day consequence of disrupted sleep. Studies attempting to quantify daytime impairment objectively in individuals with insomnia have yielded mixed results, with evidence suggesting impairments in aspects of executive functioning but not psychomotor vigilance. It has been suggested that persons with insomnia may have latent performance deficits for which they would be able to compensate effectively under normal daytime circumstances - suggesting that any such deficits may be exposed through perturbation. In this context, we used a laboratory-based total sleep deprivation (TSD) paradigm to investigate psychomotor vigilance performance in individuals with chronic sleep-onset insomnia as compared to healthy normal controls.

PARTICIPANTS AND METHODS

Fourteen participants, seven individuals with chronic sleep-onset insomnia (ages 24-40y) and seven age-matched, healthy normal sleepers completed a highly controlled in-laboratory study involving 38 h of TSD. A 10 min and a 3 min version of the psychomotor vigilance test (PVT) were administered every 3 h during TSD.

RESULTS

In both the individuals with sleep-onset insomnia and the age-matched normal sleepers, lapses of attention and false starts on the PVT were relatively infrequent during the first 16 h of the TSD period, but increased significantly when wakefulness was extended beyond 16 h. However, the effects of TSD on PVT performance were considerably exacerbated in the sleep-onset insomnia group, which showed about twice as many lapses of attention, more than twice as many false starts, and approximately twice as big a time-on-task effect on the 10 min PVT as the age-matched normal sleepers group, with similar findings on the 3 min PVT.

CONCLUSION

These findings indicate that daytime impairment reported by individuals with sleep-onset insomnia has an objective performance component that is exposed during TSD. Thus, persons with sleep-onset insomnia could be at increased risk of performance impairment in settings that involve extended wakefulness. This underscores the importance of treating insomnia and suggests that laboratory sleep deprivation studies could serve to document the effectiveness of treatment approaches.

The impact of stress on sleep: Pathogenic sleep reactivity as a vulnerability to insomnia and circadian disorders

Sleep reactivity is the trait-like degree to which stress exposure disrupts sleep, resulting in difficulty falling and staying asleep. Individuals with highly reactive sleep systems experience drastic deterioration of sleep when stressed, whereas those with low sleep reactivity proceed largely unperturbed during stress. Research shows that genetics, familial history of insomnia, female gender and environmental stress influence how the sleep system responds to stress. Further work has identified neurobiological underpinnings for sleep reactivity involving disrupted cortical networks and dysregulation in the autonomic nervous system and hypothalamic-pituitary-adrenal axis. Sleep reactivity is most pathologically and clinically pertinent when in excess, such that high sleep reactivity predicts risk for future insomnia disorder, with early evidence suggesting high sleep reactivity corresponds to severe insomnia phenotypes (sleep onset insomnia and short sleep insomnia). High sleep reactivity is also linked to risk of shift-work disorder, depression and anxiety. Importantly, stress-related worry and rumination may exploit sensitive sleep systems, thereby augmenting the pathogenicity of sleep reactivity. With the development of cost-effective assessment of sleep reactivity, we can now identify individuals at risk of future insomnia, shift-work disorder and mental illness, thus identifying a target population for preventive intervention. Given that insomniacs with high sleep reactivity tend to present with severe insomnia phenotypes, patient sleep reactivity may inform triaging to different levels of treatment. Future research on sleep reactivity is needed to clarify its neurobiology, characterize its long-term prospective associations with insomnia and shift-work disorder phenotypes, and establish its prognostic value for mental illness and other non-sleep disorders.

Poor sleep is linked to impeded recovery from traumatic brain injury

Study Objectives

While disruptions in sleep are common after mild traumatic brain injury (TBI), the longitudinal relationships between sleep problems and global functioning after injury are poorly understood. Here, we prospectively investigate risk for functional impairment during the first 6 months of TBI recovery based on sleep onset insomnia symptoms and short sleep.

Methods

Patients presenting to the Emergency Department (ED) at Johns Hopkins Hospital within 24 hours of head injury and evaluated for TBI were eligible for our study. Demographic and injury-related information were collected in the ED. Patients then completed in-person surveys and phone interviews to provide follow-up data on global functioning, sleep, and depressive symptoms at 1, 3, and 6 months post-injury. A total of 238 patients provided sufficient data for analysis, and hypotheses were tested using mixed effects modeling.

Results

Sleep quality and global functioning improved over the 6 months of TBI recovery, but patients were at increased risk for functional impairment when sleeping poorly (odds ratio [OR] = 7.69, p < .001). Sleep onset insomnia symptoms and short sleep both independently corresponded to poor global functioning. Functional impairment was highest among those with both insomnia and short sleep (43%-79%) compared to good sleepers (15%-25%) and those with short sleep (29%-33%) or insomnia alone (33%-64%). A bidirectional relationship between sleep quality and functioning was observed.

Conclusions

Functionally impaired patients diagnosed predominantly with mild TBI exhibit high rates of insomnia and short sleep, which may impede TBI recovery. Monitoring sleep after head injury may identify patients with poor prognoses and allow for early intervention to improve functional outcomes.

Sleep and Migraine: Assessment and Treatment of Comorbid Sleep Disorders

The relationship of sleep and migraine is unequivocal and familiarity with the nature and magnitude of these associations may inform clinical practice. Recent prospective, longitudinal, and time-series analysis has begun to unravel the magnitude and temporal patterns of sleep and migraine. Prospective evidence has shown that sleep variables can trigger acute migraine, precede and predict new onset headache by several years, and indeed, sleep disturbance and snoring are risk factors for chronification. The presence of a sleep disorder is associated with more frequent and severe migraine and portends a poorer headache prognosis. Interestingly, the disorders linked to migraine are quite varied, including insomnia, snoring and obstructive sleep apnea, restless legs, circadian rhythm disorders, narcolepsy, and others. Insomnia is by far the most common sleep disorder in headache patients. In fact, the majority of patients with chronic migraine presenting for treatment have insomnia. Despite a rapidly expanding literature, very few controlled treatment studies have been published to guide clinical practice. This paper focuses on clinical assessment and treatment of sleep disorders. An algorithm is presented for sleep disorders management in the migraine patient, which highlights major sleep disorders and psychiatric comorbidity. Diagnostic procedures are recommended that are conducive to clinical practice. Suggested tools include the sleep history, screening mnemonics, prediction equation, and sleep diary. New developments in treatment have produced abbreviated and cost-effective therapies for insomnia and obstructive sleep apnea that may reach a larger population. Revisions in the diagnostic manuals for sleep and headache disorders enhance recognition of sleep-related headache. Recommendations include behavioral sleep regulation, shown in recent controlled trials to decrease migraine frequency, management for sleep apnea headache, cognitive behavioral therapy (CBT) for insomnia abbreviated for the physician practice setting, sleep-related headache trigger, and others. There is no empirical evidence that sleep evaluation should delay or supersede usual headache care. Rather, sleep management is complimentary to standard headache practice.

Hyperarousal and sleep reactivity in insomnia: current insights

Hyperarousal is a key component in all modern etiological models of insomnia disorder. Overall patterns in the literature suggest that over-active neurobiological and psychological systems contribute to difficulty sleeping. Even so, mixed results regarding the specific mechanisms linking hyperarousal to sleep disturbance limit current etiological conceptualizations. Similar basal arousal profiles between individuals with high vs low risk for insomnia in the absence of stress exposure suggest that dysregulated stress "response" rather than general hyperarousal may be a more pertinent marker of risk. In this report, we discuss evidence for hyperarousal in insomnia and explore the role of sleep reactivity. A trait characteristic, sleep reactivity is the degree to which stress disrupts sleep, manifesting as difficulty falling and staying asleep. Premorbid sleep reactivity has been shown to identify individuals at risk for future insomnia disorder, such as highly reactive sleepers (whose sleep systems are sensitive to stress) who are at elevated disease risk. Research points to genetics, family history of insomnia, gender, and environmental stress as factors that influence sleep reactivity. Importantly, stress-related cognitive-emotional reactivity (e.g., rumination, worry) may exploit the vulnerability of a highly reactive sleep system. We propose that sleep reactivity and cognitive-emotional reactivity may share a bidirectional relationship, conferring an insalubrious environment for sleep in response to stress. Future research on sleep reactivity is needed to identify its neurobiology, characterize its relationship with cognitive-emotional reactivity, and explore the potential clinical utility of sleep reactivity in treatment planning.

Clinically Oriented Subtyping of Chronic Insomnia of Childhood

OBJECTIVES

To identify different profiles of pediatric insomnia, based on the most frequent clinical presentations (nocturnal awakenings, difficulty in falling asleep, nocturnal restlessness, early morning awakenings).

STUDY DESIGN

A structured parent interview was conducted in 338 children (mean age 21.29 months, SD 10.56) referred by pediatricians because of insomnia resistant to behavioral approaches and common drug treatments. The aim was to assess the characteristics of insomnia in children, together with family sleep-related history. A latent class analysis was run to identify profiles of insomnia. ANOVA and the χ² test were used to examine differences between profiles.

RESULTS

A 3-class model was built by latent class analysis: 17% (n = 58) of children constituted the first class, characterized by difficulties in falling asleep, with restlessness, nocturnal restlessness, and awakenings during the night; the second class, characterized by early morning awakenings, comprised 21% (n = 71) of children; 62% (n = 209) of children fell within the third class because of their high frequency of nocturnal awakenings and difficulties in falling asleep. The first class reported longer sleep latency and the presence of restless legs syndrome and anemia in the family history; depression and/or mood disorders were more frequent in class 2 and allergies and/or food intolerance were more frequent in class 3.

CONCLUSIONS

Our study suggests the existence of 3 different phenotypes of insomnia in children, based on clinical, personal, and familial data. The identification of these different phenotypes might help to optimize the assessment and treatment of insomnia in young children.

Nocturnal insomnia symptoms and stress-induced cognitive intrusions in risk for depression: A 2-year prospective study

Nearly half of US adults endorse insomnia symptoms. Sleep problems increase risk for depression during stress, but the mechanisms are unclear. During high stress, individuals having difficulty falling or staying asleep may be vulnerable to cognitive intrusions after stressful events, given that the inability to sleep creates a period of unstructured and socially isolated time in bed. We investigated the unique and combined effects of insomnia symptoms and stress-induced cognitive intrusions on risk for incident depression. 1126 non-depressed US adults with no history of DSM-5 insomnia disorder completed 3 annual web-based surveys on sleep, stress, and depression. We examined whether nocturnal insomnia symptoms and stress-induced cognitive intrusions predicted depression 1y and 2y later. Finally, we compared depression-risk across four groups: non-perseverators with good sleep, non-perseverators with insomnia symptoms, perseverators with good sleep, and perseverators with insomnia symptoms. Insomnia symptoms (β = .10-.13, p < .001) and cognitive intrusions (β = .19-.20, p < .001) predicted depression severity 1y and 2y later. Depression incidence across 2 years was 6.2%. Perseverators with insomnia had the highest rates of depression (13.0%), whereas good sleeping non-perseverators had the lowest rates (3.3%, Relative Risk = 3.94). Perseverators with sleep latency >30 m reported greater depression than good sleeping perseverators (t = 2.09, p < .04). Cognitive intrusions following stress creates a depressogenic mindset, and nocturnal wakefulness may augment the effects of cognitive arousal on depression development. Poor sleepers may be especially vulnerable to cognitive intrusions when having difficulty initiating sleep. As treatable behaviors, nighttime wakefulness and cognitive arousal may be targeted to reduce risk for depression in poor sleepers.

Characterization of Patients Who Present With Insomnia: Is There Room for a Symptom Cluster-Based Approach?

STUDY OBJECTIVES

This study examined empirically derived symptom cluster profiles among patients who present with insomnia using clinical data and polysomnography.

METHODS

Latent profile analysis was used to identify symptom cluster profiles of 175 individuals (63% female) with insomnia disorder based on total scores on validated self-report instruments of daytime and nighttime symptoms (Insomnia Severity Index, Glasgow Sleep Effort Scale, Fatigue Severity Scale, Beliefs and Attitudes about Sleep, Epworth Sleepiness Scale, Pre-Sleep Arousal Scale), mean values from a 7-day sleep diary (sleep onset latency, wake after sleep onset, and sleep efficiency), and total sleep time derived from an in-laboratory PSG.

RESULTS

The best-fitting model had three symptom cluster profiles: "High Subjective Wakefulness" (HSW), "Mild Insomnia" (MI) and "Insomnia-Related Distress" (IRD). The HSW symptom cluster profile (26.3% of the sample) reported high wake after sleep onset, high sleep onset latency, and low sleep efficiency. Despite relatively comparable PSG-derived total sleep time, they reported greater levels of daytime sleepiness. The MI symptom cluster profile (45.1%) reported the least disturbance in the sleep diary and questionnaires and had the highest sleep efficiency. The IRD symptom cluster profile (28.6%) reported the highest mean scores on the insomnia-related distress measures (eg, sleep effort and arousal) and waking correlates (fatigue). Covariates associated with symptom cluster membership were older age for the HSW profile, greater obstructive sleep apnea severity for the MI profile, and, when adjusting for obstructive sleep apnea severity, being overweight/obese for the IRD profile.

CONCLUSIONS

The heterogeneous nature of insomnia disorder is captured by this data-driven approach to identify symptom cluster profiles. The adaptation of a symptom cluster-based approach could guide tailored patient-centered management of patients presenting with insomnia, and enhance patient care.

DSM-5 Insomnia and Short Sleep: Comorbidity Landscape and Racial Disparities

STUDY OBJECTIVES

We estimated rates of cardiometabolic disease, pain conditions, and psychiatric illness associated with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) insomnia disorder (current and in remission) and habitual short sleep (fewer than 6 h), and examined the roles of insomnia and short sleep in racial disparities in disease burden between black and non-Hispanic white Americans.

METHODS

This epidemiological survey study was cross-sectional. The community-based sample consisted of 3,911 subjects (46.0 y ± 13.3; 65.4% female; 25.0% black) across six sleep groups based on DSM-5 insomnia classification (never vs. remitted vs. current) and self-reported habitual sleep duration (normal vs. short). Vascular events, cardiometabolic disease, pain conditions, and psychiatric symptoms were self-reported.

RESULTS

Short sleeping insomniacs were at elevated risk for myocardial infarction, stroke, treated hypertension, diabetes, chronic pain, back pain, depression, and anxiety, independent of sex, age, and obesity. Morbidity profiles for insomniacs with normal sleep duration and former insomniacs, irrespective of sleep duration, were similar with elevations in treated hypertension, chronic pain, depression, and anxiety. Regarding racial disparities, cardiometabolic and psychiatric illness burden was greater for blacks, who were more likely to have short sleep and the short sleep insomnia phenotype. Evidence suggested that health disparities may be attributable in part to race-related differences in sleep.

CONCLUSIONS

Insomnia disorder with short sleep is the most severe phenotype of insomnia and comorbid with many cardiometabolic and psychiatric illnesses, whereas morbidity profiles are highly similar between insomniacs with normal sleep duration and former insomniacs. Short sleep endemic to black Americans increases risk for the short sleep insomnia phenotype and likely contributes to racial disparities in cardiometabolic disease and psychiatric illness.

Prevalence and Predictors of Prescription Sleep Aid Use among Individuals with DSM-5 Insomnia: The Role of Hyperarousal

STUDY OBJECTIVES

Despite mounting evidence for the overuse of prescription sleep aids (PSA), reliable data on PSA use among insomniacs are unavailable. Current studies focus on trends in PSA use at the general population level, and thus do not distinguish between transient sleep disturbance and insomnia disorder. Therefore, we prospectively examined the prevalence and predictors of baseline and chronic PSA use in a well-defined sample of individuals with insomnia.

METHODS

We analyzed longitudinal data from an urban, community-based cohort of 649 adults (48.1 ± 11.6 y; 69.3% female) with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)-based insomnia disorder. Participants completed standardized measures of sleep disturbance, daytime alertness, depression, and anxiety at baseline and follow-up 1 y later. They also reported whether and with what frequency they used PSA at both time points.

RESULTS

Approximately 19% of the sample used PSA at baseline, the majority (69.4%) of whom continued use 1 y later. Anxiety and daytime alertness were the only independent predictors of both acute and chronic PSA use. An increase of 1 standard deviation (SD) in alertness was associated with a 33% increase in the odds of chronic PSA use (χ(2) = 4.98; odds ratio [OR] = 1.33; 95% confidence interval [CI]: 1.04-1.72; P < 0.05), and a 1-SD increase in anxiety was associated with a 41% increase (χ(2) = 6.95; OR = 1.41; 95% CI: 1.09-1.82; P < 0.05). Chronic PSA users did not report any significant improvements in sleep from baseline to follow-up relative to nonusers.

CONCLUSIONS

Hyperarousal, as indexed by daytime alertness and anxiety, is a strong determinant of PSA use among individuals with insomnia. These findings are consistent with emerging data showing that insomnia is not just a nocturnal sleep disorder, but one characterized by 24-h arousal. Though current research targets sleep disturbance, this study highlights the role of the arousal system in pharmacological treatment seeking.

Towards quantitative cutoffs for insomnia: how current diagnostic criteria mischaracterize remission

OBJECTIVE

Although sleep symptoms of insomnia can be quantified, none of the current diagnostic systems stipulate quantitative cutoffs for sleep-onset latency (SOL) or wake time after sleep onset (WASO). Diagnoses are based instead on idiographic patient reports of "difficulty" falling/staying asleep. Therefore, we examined whether remission of insomnia as per the diagnostic criteria results from a normalization of quantitative sleep disturbance, or if it is simply reflective of tolerance to sleep symptoms.

METHODS

This study involved a yearlong prospective investigation of 649 adults (48.1 ± 11.6 years; 69.3% female) with DSM-5-based insomnia. Participants completed measures of sleep disturbance, perceived sleep-related distress, daytime sleepiness, functional impairment, and workplace productivity at baseline and follow-up one year later.

RESULTS

A total of 271 participants no longer met the DSM-5-based insomnia criteria at follow-up. However, 66% of these remitters reported ≥31 min of SOL and/or WASO. Daytime impairment in this subgroup of remitters was no different from that among individuals who met the diagnostic criteria at both baseline and follow-up (ie, chronic insomniacs). By contrast, follow-up impairment was significantly lower (F = 12.3; P < 0.01) among remitters whose sleep disturbance returned below empirically derived quantitative cutoffs (both SOL and WASO <31 min) than in chronic insomniacs.

CONCLUSION

This is the first study on the long-term course of insomnia based on the newly established DSM-5 criteria. A troubling implication of findings is that a majority of insomniacs stop meeting the diagnostic criteria despite continued sleep disturbance and impairment. "Remission" in these cases is attributable instead to tolerance of sleep symptoms. Incorporating quantitative criteria into current diagnoses may offer a more sensitive assay of treatment needs.

Identifying At-Risk Individuals for Insomnia Using the Ford Insomnia Response to Stress Test

STUDY OBJECTIVES

A primary focus of the National Institute of Mental Health's current strategic plan is "predicting" who is at risk for disease. As such, the current investigation examined the utility of premorbid sleep reactivity in identifying a specific and manageable population at elevated risk for future insomnia.

METHODS

A community-based sample of adults (n = 2,892; 59.3% female; 47.9 ± 13.3 y old) with no lifetime history of insomnia or depression completed web-based surveys across three annual assessments. Participants reported parental history of insomnia, demographic characteristics, sleep reactivity on the Ford Insomnia in Response to Stress Test (FIRST), and insomnia symptoms. DSM-IV diagnostic criteria were used to determine insomnia classification.

RESULTS

Baseline FIRST scores were used to predict incident insomnia at 1-y follow-up. Two clinically meaningful FIRST cutoff values were identified: FIRST ≥ 16 (sensitivity 77%; specificity 50%; odds ratio [OR] = 2.88, P < 0.001); and FIRST ≥ 18 (sensitivity 62%; specificity 67%; OR = 3.32, P < 0.001). Notably, both FIRST cut-points outperformed known maternal (OR = 1.49-1.59, P < 0.01) and paternal history (P = NS) in predicting insomnia onset, even after controlling for stress exposure and demographic characteristics. Of the incident cases, insomniacs with highly reactive sleep systems reported longer sleep onset latencies (FIRST ≥ 16: 65 min; FIRST ≥ 18: 68 min) than participants with nonreactive insomnia (FIRST < 16: 37 min; FIRST < 18: 44 min); these groups did not differ on any other sleep parameters.

CONCLUSIONS

The current study established a cost- and time-effective strategy for identifying individuals at elevated risk for insomnia based on trait sleep reactivity. The FIRST accurately identifies a focused target population in which the psychobiological processes complicit in insomnia onset and progression can be better investigated, thus improving future preventive efforts.

Shift work disorder, depression, and anxiety in the transition to rotating shifts: the role of sleep reactivity

AIM

The aim of this study is to investigate premorbid sleep reactivity as a vulnerability to incident shift work disorder (SWD), and related changes in depression as well as anxiety following a transition to a rotating shifts work schedule.

METHODS

This is a longitudinal study with two waves of data collection. The community-based sample included normal sleeping non-shift workers (N = 96; 62.5% female; 47.9 ± 13.3 years) without a lifetime history of insomnia or baseline excessive daytime sleepiness who transitioned to rotating shift work one year later. Participants reported demographic characteristics, trait sleep reactivity on the Ford Insomnia Response to Stress Test, depression symptoms on the Quick Inventory of Depression Symptomatology, and anxiety symptoms on the Beck Anxiety Inventory. SWD was determined based on significant sleep disturbance and/or excessive sleepiness in the context of working in a rotating-shift schedule.

RESULTS

Analyses revealed that the odds were over five times greater for highly sleep-reactive individuals to develop SWD after transitioning to rotating shifts (OR = 5.59, p = 0.04). Nearly 90% of participants who suffered from SWD were accurately identified as high risk at one year before disease onset. Furthermore, individuals who developed SWD reported greater increases in symptoms of depression and anxiety. Finally, analyses revealed significant indirect effects wherein high sleep reactivity increased risk for SWD, which led to greater severity of anxiety and depression symptoms.

CONCLUSIONS

The Ford Insomnia Response to Stress Test (FIRST) accurately identifies a focused target population in which the premorbid psychobiological processes complicit in SWD onset and progression, as well as shift work-related depression and anxiety changes, can be better investigated, thus improving future preventative efforts.

Insomnia disorder

Insomnia disorder affects a large proportion of the population on a situational, recurrent or chronic basis and is among the most common complaints in medical practice. The disorder is predominantly characterized by dissatisfaction with sleep duration or quality and difficulties initiating or maintaining sleep, along with substantial distress and impairments of daytime functioning. It can present as the chief complaint or, more often, co-occurs with other medical or psychiatric disorders, such as pain and depression. Persistent insomnia has been linked with adverse long-term health outcomes, including diminished quality of life and physical and psychological morbidity. Despite its high prevalence and burden, the aetiology and pathophysiology of insomnia is poorly understood. In the past decade, important changes in classification and diagnostic paradigms have instigated a move from a purely symptom-based conceptualization to the recognition of insomnia as a disorder in its own right. These changes have been paralleled by key advances in therapy, with generic pharmacological and psychological interventions being increasingly replaced by approaches that have sleep-specific and insomnia-specific therapeutic targets. Psychological and pharmacological therapies effectively reduce the time it takes to fall asleep and the time spent awake after sleep onset, and produce a modest increase in total sleep time; these are outcomes that correlate with improvements in daytime functioning. Despite this progress, several challenges remain, including the need to improve our knowledge of the mechanisms that underlie insomnia and to develop more cost-effective, efficient and accessible therapies.

The Anxiolytic Effects of Cognitive Behavior Therapy for Insomnia: Preliminary Results from a Web-delivered Protocol

Though the efficacy of cognitive behavior therapy for insomnia (CBTI) is well-established, the paucity of credentialed providers hinders widespread access. Further, the impact of alternatives such as web-delivered CBTI has not been adequately tested on common insomnia comorbidities such as anxiety. Therefore, we assessed the impact of an empirically validated web-delivered CBTI intervention on insomnia and comorbid anxiety symptoms. A sample of 22 adults (49.8±13.5 yo; 62.5% female) with DSM-5 based insomnia were randomized to either an active CBTI treatment group (n = 13) or an information-control (IC) group (n = 9). Participants in the CBTI group underwent a standard CBTI program delivered online by a 'virtual' therapist, whereas the IC group received weekly 'sleep tips' and general sleep hygiene education via electronic mail. All participants self-reported sleep parameters, including sleep onset latency (SOL), insomnia symptoms per the Insomnia Severity Index (ISI), and anxiety symptoms per the Beck Anxiety Inventory (BAI) at both baseline as well as follow- up assessment one week post-treatment. There were no significant differences between the CBTI and IC groups on baseline measures. The CBTI group showed significantly larger reductions in BAI scores (t = 2.6; p < .05; Cohen's d = .8) and ISI scores (t = 2.1; p < .05; Cohen's d = .9) at follow-up than did the IC group. Further, changes in SOL from baseline (62.3±44.0 minutes) to follow-up (22.3±14.4 minutes) in the CBTI group were also significantly greater (t = 2.3; p < .05; Cohen's d = .9) than in the IC group (baseline: 55.0±44.2 minutes; follow-up: 50.±60.2 minutes). This study offers preliminary evidence that a web-delivered CBTI protocol with minimal patient contact can improve comorbid anxiety symptoms among individuals with insomnia.