Use of Sleep Aids in Insomnia: The Role of Time Monitoring Behavior.

Objective: Over-the-counter (OTC) and prescription sleep medications are frequently used as treatments for chronic insomnia, despite risks and limited long-term efficacy. Investigating mechanisms underlying this predilection for pharmacotherapy may uncover strategies to decrease reliance on sleep aids. The objective of this study was to determine how time monitoring behavior (TMB; clock-watching) and associated frustration may interact with insomnia symptoms to drive the use of sleep aids.Methods: Patients (N = 4,886) presenting for care at a community-based, private sleep medical center between May 2003 and October 2013 completed the Insomnia Severity Index (ISI) and Time Monitoring Behavior-10 (TMB-10) and reported their frequency of sleep medication use (OTC and prescription, separately). Mediation analyses examined how clock-watching and related frustration could be associated with insomnia symptoms and medication use.Results: The relationship between TMB and sleep medication use was significantly explained by ISI (P < .05), in that TMB (especially related frustration) appears to aggravate insomnia, which in turn leads to sleep aid use. Similarly, but to a lesser extent, the relationship between ISI and sleep medication use was explained by TMB, in that ISI may lead to increased TMB, which may in turn lead to sleep aid use.Conclusions: TMB and the associated frustration it engenders may perpetuate a negative cycle of insomnia and sleep aid use. Future longitudinal and interventional research is necessary to examine the developmental course of these clinical symptoms and behaviors and to test whether decreasing frustration by limiting TMB reduces the proclivity for pharmacotherapy.

Psychometric properties of the Disturbing Dream and Nightmare Severity Index-Korean version.

STUDY OBJECTIVES: This study aimed to examine psychometric properties of the Disturbing Dream and Nightmare Severity Index (DDNSI) in individuals aged between 18 and 39. METHODS: All participants (n = 674) were asked to complete the DDNSI, including the modified Nightmare Effects Survey. Additionally, 109 participants were tested for test-retest reliability after 3 months. Among our sample, 229 (33.9%) reported having at least 1 nightmare per month. RESULTS: Internal consistency was evaluated for the total sample (Cronbach's α = .920) and separately for individuals reporting more than once per month (Cronbach's α = .755). Test-retest reliability after 3 months was .705. Convergent validity of the DDNSI with Nightmare Effects Survey was also satisfactory (r = .638, P < .001). Finally, exploratory factor analysis was conducted to explore the construct of the DDNSI, and results indicated that it consisted of 2 factors, nightmare frequency and nightmare distress [χ²(df) = 2.241(1) ∆χ² (∆df) = 155.575(4), Tucker-Lewis incremental fit index = .980, root mean square error of approximation (90% confidence interval) = .074 (0, .208), standardized root-mean-square residual = .011]. CONCLUSIONS: The DDNSI is a reliable measure of nightmare severity that can be used in various settings.

The PAP-NAP one decade later: patient risk factors, indications, and clinically relevant emotional and motivational influences on PAP use.

STUDY OBJECTIVES: Positive airway pressure (PAP) noncompliance remains a major barrier in obstructive sleep apnea (OSA) treatment. The PAP-NAP, a daytime PAP "test-drive," has been associated with increased PAP use, but risk factors and indications for the procedure remain unspecified. METHODS: A retrospective chart review was conducted on 139 patients who (1) were diagnosed with OSA (n = 116) or upper airway resistance syndrome (UARS) (n = 23); (2) adamantly refused to proceed with either a full-night attended titration or in-home trial of PAP; and (3) elected to proceed with a PAP-NAP instead. Risk factors for PAP rejection (identified on intake) and indications for the PAP-NAP (identified post-diagnostic polysomnography) were confirmed through multiple encounters with sleep center personnel. All patients completed the PAP-NAP, which utilizes an elaborate desensitization program to provide a less challenging introduction and facilitate a gentler adaptation to pressurized air as well as to test advanced PAP modes when subjective or objective expiratory pressure intolerance emerges. Both emotional aversion toward and lack of motivation for PAP therapy were assessed pre- and post-PAP-NAP. PAP use was determined several months post-procedure. RESULTS: At intake, most common risk factors for PAP rejection were depression, insomnia, and claustrophobia; most common indications for PAP-NAP were general reluctance, anxiety, and claustrophobia. Procedure averaged 3+ hours [tech coaching, 83 (± 30) min; napping, 107 (± 57) min]. Ninety-nine percent required advanced PAP. Compared to baseline, emotional aversion (p = 0.0001) and motivation (p = 0.0001) significantly improved for the entire sample of which 86% completed full-night titrations and 78% filled PAP prescriptions. At final follow-up, 71% (n = 98) were users and 29% (n = 41) were non-users. Compared to non-users, users showed significantly greater decreases in emotional aversion (p < 0.001; Z = - 6.11) and greater increases in motivation (p < 0.001; Z = - 8.57). CONCLUSION: PAP-NAP was associated with a sizeable proportion of highly reluctant patients proceeding to titrations they initially had rejected, and the majority achieved PAP user status. Improvements in emotional aversion and motivation were associated with increased PAP use. Randomized control trials must assess the experiential component at the core of the PAP-NAP procedure and its efficacy in reversing early PAP rejecters.

Prospective Randomized Controlled Trial on the Efficacy of Continuous Positive Airway Pressure and Adaptive Servo-Ventilation in the Treatment of Chronic Complex Insomnia.

BACKGROUND: Complex insomnia, the comorbidity of chronic insomnia and obstructive sleep apnea (OSA), is a common sleep disorder, but the OSA component, whether presenting overtly or covertly, often goes unsuspected and undiagnosed due to a low index of suspicion. Among complex insomniacs, preliminary evidence demonstrates standard CPAP decreases insomnia severity. However, CPAP causes expiratory pressure intolerance or iatrogenic central apneas that may diminish its use. An advanced PAP mode-adaptive servo-ventilation (ASV)-may alleviate CPAP side-effects and yield superior outcomes. METHODS: In a single-site protocol investigating covert complex insomnia (ClinicalTrials.gov identifier: NCT02365064), a low index of suspicion for this comorbidity was confirmed by exclusion of 455 of 660 eligible patients who presented during the study period with overt OSA signs and symptoms. Ultimately, stringent inclusion/exclusion criteria to test efficacy yielded 40 adult, covert complex insomnia patients [average Insomnia Severity Index (ISI) moderate-severe 19.30 (95% CI 18.42-20.17)] who reported no definitive OSA symptoms or risks and who failed behavioral or drug therapy for an average of one decade. All 40 were diagnosed with OSA and randomized (using block randomization) to a single-blind, prospective protocol, comparing CPAP (n = 21) and ASV (n = 19). Three successive PAP titrations fine-tuned pressure settings, facilitated greater PAP use, and collected objective sleep and breathing data. Patients received 14 weeks of treatment including intensive biweekly coaching and follow-up to foster regular PAP use in order to accurately measure efficaciousness. Primary outcomes measured insomnia severity and sleep quality. Secondary outcomes measured daytime impact: OSA-induced impairment, fatigue severity, insomnia impairment, and quality of life. Performance on these seven variables was assessed using repeated measures ANCOVA to account for the multiple biweekly time points. FINDINGS: At intake, OSA diagnosis and OSA as a cause for insomnia were denied by all 40 patients, yet PAP significantly decreased insomnia severity scores (p = 0.021 in the primary ANCOVA analysis). To quantify effect sizes, mean intake vs endpoint analysis was conducted with ASV yielding nearly twice the effects of CPAP [- 13.2 (10.7-15.7), Hedges' g = 2.50 vs - 9.3 (6.3-12.3), g = 1.39], and between mode effect size was in the medium-large range 0.65. Clinically, ASV led to remission (ISI < 8) in 68% of cases compared to 24% on CPAP [Fisher's exact p = 0.010]. Two sleep quality measures in the ANCOVA analysis again demonstrated superior significant effects for ASV compared to CPAP (both p < 0.03), and pre- and post-analysis demonstrated substantial effects for both scales [ASV (g = 1.42; g = 1.81) over CPAP (g = 1.04; g = 0.75)] with medium size effects between modes (0.54, 0.51). Measures of impairment, residual objective sleep breathing events, and normalized breathing periods consistently demonstrated larger beneficial effects for ASV over CPAP. INTERPRETATION: PAP therapy was highly efficacious in decreasing insomnia severity in chronic insomnia patients with previously undiagnosed co-morbid OSA. ASV proved superior to CPAP in this first efficacy trial to compare advanced to traditional PAP modes in complex insomnia. Future research must determine the following: pathophysiological mechanisms to explain how OSA causes chronic insomnia; general population prevalence of this comorbidity; and, cost-effectiveness of ASV therapy in complex insomnia. Last, efforts to raise awareness of complex insomnia are urgently needed as patients and providers appear to disregard both overt and covert signs and symptoms of OSA in the assessment of chronic insomnia.

Changes in insomnia severity with advanced PAP therapy in patients with posttraumatic stress symptoms and comorbid sleep apnea: a retrospective, nonrandomized controlled study.

BACKGROUND: Sleep disorders frequently occur in posttraumatic stress disorder (PTSD) patients. Chronic insomnia is a common feature of and criteria for the diagnosis of PTSD. Another sleep disorder, obstructive sleep apnea (OSA), also occurs frequently in PTSD, and emerging research indicates OSA fuels chronic insomnia. Scant research has investigated the impact of OSA treatment on insomnia outcomes (Insomnia Severity Index, ISI) in trauma survivors. METHODS: OSA patients with moderately severe posttraumatic stress symptoms were studied in a retrospective chart review. Ninety-six patients who failed CPAP therapy due to expiratory pressure intolerance or complex sleep apnea or both underwent manual titration with advanced PAP modes [autobilevel (ABPAP); adaptive servo-ventilation (ASV)], which were subsequently prescribed. PAP use measured by objective data downloads divided the sample into three groups: compliant regular users (C-RU): n = 68; subthreshold users (SC-RU): n = 12; and noncompliant users (NC-MU): n = 16. The average follow-up was 11.89 ± 12.22 months. Baseline and posttreatment ISI scores were analyzed to assess residual insomnia symptoms as well as cure rates. RESULTS: The C-RU group showed significant improvements in insomnia with very large effects compared to those in the NC-MU reference group (P = 0.019). Insomnia severity significantly decreased in all three groups with large effects (C-RU, P = 0.001; SC-RU, P = 0.027; NC-MU, P = 0.007). Hours of weekly PAP use and insomnia severity were inversely correlated (P = 0.001, r = - 0.321). However, residual insomnia symptoms based on established ISI cut-offs were quite common, even among the C-RU group. Post hoc analysis showed that several categories of sedating medications reported at baseline (hypnotics, anti-epileptic, opiates) as well as actual use of any sedating medication (prescription or nonprescription) were associated with smaller insomnia improvements than those in patients not using any sedating agents. CONCLUSIONS: In a retrospective, nonrandomized analysis of a select sample of sleep clinic patients with OSA and PTSD symptoms, advanced PAP therapy was associated with significant improvement in insomnia severity for both compliant and partial users. However, residual insomnia symptoms persisted, indicating that PAP therapy provides only limited treatment. RCTs are warranted to assess the effect of ABPAP and ASV modes of therapy on adherence and sleep outcomes, and their potential impact on posttraumatic stress symptoms. Treatment arms that combine PAP with CBT-I would be expected to yield the greatest potency.

Aetiology and treatment of nightmare disorder: State of the art and future perspectives.

This consensus paper provides an overview of the state of the art in research on the aetiology and treatment of nightmare disorder and outlines further perspectives on these issues. It presents a definition of nightmares and nightmare disorder followed by epidemiological findings, and then explains existing models of nightmare aetiology in traumatized and non-traumatized individuals. Chronic nightmares develop through the interaction of elevated hyperarousal and impaired fear extinction. This interplay is assumed to be facilitated by trait affect distress elicited by traumatic experiences, early childhood adversity and trait susceptibility, as well as by elevated thought suppression and potentially sleep-disordered breathing. Accordingly, different treatment options for nightmares focus on their meaning, on the chronic repetition of the nightmare or on maladaptive beliefs. Clinically, knowledge of healthcare providers about nightmare disorder and the delivery of evidence-based interventions in the healthcare system is discussed. Based on these findings, we highlight some future perspectives and potential further developments of nightmare treatments and research into nightmare aetiology.

Nightmares and suicide risk in psychiatric patients: The roles of hopelessness and male depressive symptoms.

Although nightmares have been shown to increase the risk for suicide, less is known about the mechanisms underlying this relationship. In order to address this gap and guided by the hopelessness theory of suicide risk, we examined hopelessness and male depressive symptoms as risk factors for suicide while considering the frequency of and impairment due to nightmares. Data were collected from 172 psychiatrically hospitalized, adult patients (91 women, 81 men) with an average age of 39.15 (SD = 13.48) years. Patients were administered self-report measures of nightmare frequency/impairment, hopelessness, and male depressive symptoms, as well as undergoing a fully structured diagnostic clinical interview to determine diagnoses and suicide risk. Compared to patients with yearly or no nightmares, those with monthly or weekly nightmares reported nightmares reported higher levels of hopelessness, male depressive symptoms, and suicide risk. Male depressive symptoms significantly mediated the relation between hopelessness and suicide risk in patients who reported monthly to weekly nightmares, but not in those who reported yearly or no nightmares. Moreover, impairment due to nightmares was significantly and positively associated with male depression, but not hopelessness or suicide risk. The results also provide evidence and further understanding about possible mechanisms of emerging suicide.

Mental Health Effects of Stress over the Life Span of Refugees.

Information about the relative impact of stressful events across the lifespan on the mental health of refugees is needed. Cross-sectional data from a community sample of 135 Kurdish and 117 Vietnamese refugees were fit to a path model about the effects of non-war stress, war-related stress, and post-migration stress on mental health. Kurdish and Vietnamese data were generally consistent with the model. However, war-related stress produced no direct but a large indirect effect through post-migration stress on mental health in Kurds. Vietnamese data indicated a modest direct war-related stress effect but no indirect influence through post-migration stress. Different types of stressful events lead to adverse mental health of displaced refugees in a somewhat group-dependent manner. Implications for prevention and treatment are discussed.

Sleep disorder prevalence in at-risk adolescents and potential effects of nightmare triad syndrome.

Objective At-risk high school students, those considered to have a higher probability for academic failure or dropping out, were assessed for various sleep disorders. Effects were compared between students with and without the nightmare triad syndrome (NTS+), the sleep disorders' cluster of frequent nightmares, insomnia disorder and suspected sleep-disordered breathing (SDB). Methods Data were gathered at a charter school for at-risk youth using: computer based surveys, physical airway exams, and mental health interviews by school social worker. Ninety-two students were enrolled, and 70 completed all study components. Results Students were teenaged [17.10 (1.50) years], male (52.2%) slightly overweight [BMI 25.50 (6.41)] Hispanics (87.0%); two-thirds (65 of 92) subjectively reported a sleep problem. Frequent nightmares (39.1%), insomnia (ISI ≥ 12, 41.3%), and SDB risk (79.3%) were common. Several presumptive sleep disorders (insomnia, SDB risk, parasomnia, or nightmares) were associated with worse sleep quality and lower quality of life. Nineteen students met criteria for NTS. Compared to NTS-, NTS+ showed significantly lower quality of life (p < 0.003, g = 0.84). Regression analyses revealed higher levels of depression and anxiety symptoms in NTS+ students. NTS was associated with reduced quality of life independent of anxiety symptoms. Conclusion Prevalence of presumptive sleep disorders was high with a tendency for clusters of sleep disorders in the same individual. Students with NTS+ showed worse outcomes and reduced quality of life, mediated partially by depression and anxiety. To examine relationships between sleep disorders and mental health in at-risk adolescents, research investigations must include both subjective and objective measurements of sleep.

Positive airway pressure adherence and subthreshold adherence in posttraumatic stress disorder patients with comorbid sleep apnea.

STUDY OBJECTIVES: Patients with comorbid posttraumatic stress disorder (PTSD) and obstructive sleep apnea (OSA) manifest low adherence to continuous positive airway pressure (CPAP) due to fixed, pressure-induced expiratory pressure intolerance (EPI), a subjective symptom and objective sign aggravated by anxiety sensitivity and somatosensory amplification. As advanced PAP therapy modes (ie, auto-bilevel PAP [ABPAP] or adaptive servo-ventilation [ASV]) may address these side effects, we hypothesized such treatment would be associated with decreased expiratory intolerance and increased adherence in posttraumatic stress patients with co-occurring OSA. METHODS: We reviewed charts of 147 consecutive adult patients with moderately severe posttraumatic stress symptoms and objectively diagnosed OSA. All patients failed or rejected CPAP and were manually titrated on auto-adjusting, dual-pressure ABPAP or ASV modes in the sleep laboratory, a technique to eliminate flow limitation breathing events while resolving EPI. Patients were then prescribed either mode of therapy. Follow-up encounters assessed patient use, and objective data downloads (ODDs) measured adherence. RESULTS: Of 147 charts reviewed, 130 patients were deemed current PAP users, and 102 provided ODDs: 64 used ASV and 38 used ABPAP. ODDs yielded three groups: 59 adherent per insurance conventions, 19 subthreshold compliant partial users, and 24 noncompliant. Compliance based on available downloads was 58%, notably higher than recently reported rates in PTSD patients with OSA. Among the 19 partial users, 17 patients were minutes of PAP use or small percentages of nights removed from meeting insurance compliance criteria for PAP devices. CONCLUSION: Research is warranted on advanced PAP modes in managing CPAP failure in PTSD patients with comorbid OSA. Subthreshold adherence constructs may inform clinical care in a patient-centric model distinct from insurance conventions. Speculatively, clinical application of this transitional zone ("subthreshold" number of hours) may increase PAP use and eventual adherence.

Retrospective, nonrandomized controlled study on autoadjusting, dual-pressure positive airway pressure therapy for a consecutive series of complex insomnia disorder patients.

PURPOSE: Emerging evidence shows that positive airway pressure (PAP) treatment of obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) in chronic insomnia patients (proposed "complex insomnia" disorder) leads to substantial decreases in insomnia severity. Although continuous PAP (CPAP) is the pressure mode most widely researched, intolerance to fixed pressurized air is rarely investigated or described in comorbidity patients. This retrospective study examined dual pressure, autoadjusting PAP modes in chronic, complex insomnia disorder patients. PATIENTS AND METHODS: Chronic insomnia disorder patients (mean [SD] insomnia severity index [ISI] =19.11 [3.34]) objectively diagnosed with OSA or UARS and using either autobilevel PAP device or adaptive servoventilation (ASV) device after failing CPAP therapy (frequently due to intolerance to pressurized air, poor outcomes, or emergence of CSA) were divided into PAP users (≥20 h/wk) and partial users (<20 h/wk) for comparison. Subjective and objective baseline and follow-up measures were analyzed. RESULTS: Of the 302 complex insomnia patients, PAP users (n=246) averaged 6.10 (1.78) nightly hours and 42.71 (12.48) weekly hours and partial users (n=56) averaged 1.67 (0.76) nightly hours and 11.70 (5.31) weekly hours. For mean (SD) decreases in total ISI scores, a significant (group × time) interaction was observed (F[1,300]=13.566; P<0.0001) with PAP users (-7.59 [5.92]; d=1.63) showing superior results to partial users (-4.34 [6.13]; d=0.81). Anecdotally, patients reported better tolerability with advanced PAP compared to previous experience with CPAP. Both adaptive servoventilation and autobilevel PAP showed similar ISI score improvement without statistical differences between devices. Total weekly hours of PAP use correlated inversely with change in insomnia symptoms (r=-0.256, P<0.01). CONCLUSION: Insomnia severity significantly decreased in patients using autoadjusting PAP devices, but the study design restricts interpretation to an association. Future research must elucidate the interaction between insomnia and OSA/UARS as well as the adverse influence of pressure intolerance on PAP adaptation in complex insomnia patients. Randomized controlled studies must determine whether advanced PAP modes provide benefits over standard CPAP modes in these comorbidity patients.

Reversal of PAP Failure With the REPAP Protocol.

BACKGROUND: Re-titrations, an atypical approach to reverse PAP failure, was investigated retrospectively. METHODS: Application of our re-titration of PAP (REPAP) protocol in subjects with previous PAP failure assessed original technology (masks, modes, and pressures) in 273 subjects, of which 70% reported co-occurring psychiatric conditions. The REPAP protocol emphasized changes in pressure modes and settings to address expiratory pressure intolerance and residual breathing events; mask changes were facilitated. Objective sleep and breathing metrics and subjective post-titration ratings were analyzed in subsequent PAP users and non-users. RESULTS: Following REPAP protocol (average follow-up = 2 y), 196 of 273 subjects with previous PAP failure were PAP users, and 77 were non-users. Previous PAP failure was attributed to technology factors, including pressure intolerance, mask discomfort, adaptation difficulties, and no benefits. At second opinion re-titration, mask changes resolved discomfort, mouth breathing, or leak (91.2% of sample); pressure mode changes resolved expiratory pressure intolerance (83.5%); and pressure setting changes decreased residual breathing events and improved air flow (96.7%), all of which were associated with renewed PAP use. PAP users showed objective sleep improvements on re-titrations and reported better sleep quality than non-users. Multiple logistic regressions showed 2 subjective, re-initiation predictors: (1) post-re-titration ratings of better sleep quality and (2) less anticipated difficulty in using PAP after initial or multiple re-titrations. User rates were significantly higher for subjects completing multiple (n = 158) versus one (n = 115) re-titration (80% vs 61%, P = .001). In multiple re-titration subjects, PAP users showed significance or a trend for lower apnea-hypopnea index (P = .02, g = 0.48) and respiratory disturbance index (P = .07, g = 0.36) compared with non-users. Available user downloads averaged >5 h/night. CONCLUSIONS: Technology-related problems due to mask discomfort/leak, pressure intolerance, and residual breathing events were associated with PAP failure in subjects seeking second opinions. Technological solutions (changes in masks, modes, and pressures) were addressed during REPAP protocol, after which 72% of subjects re-initiated PAP use. These technological interventions were associated with improved objective and subjective sleep variables and reversal of PAP failure.

A Novel Therapy for Chronic Sleep-Onset Insomnia: A Retrospective, Nonrandomized Controlled Study of Auto-Adjusting, Dual-Level, Positive Airway Pressure Technology.

OBJECTIVE: Evidence indicates that behavioral or drug therapy may not target underlying pathophysiologic mechanisms for chronic insomnia, possibly due to previously unrecognized high rates (30%-90%) of sleep apnea in chronic insomnia patients. Although treatment studies with positive airway pressure (PAP) demonstrate decreased severity of chronic sleep maintenance insomnia in patients with co-occurring sleep apnea, sleep-onset insomnia has not shown similar results. We hypothesized advanced PAP technology would be associated with decreased sleep-onset insomnia severity in a sample of predominantly psychiatric patients with comorbid sleep apnea. METHODS: We reviewed charts of 74 severe sleep-onset insomnia patients seen from March 2011 to August 2015, all meeting American Academy of Sleep Medicine Work Group criteria for a chronic insomnia disorder and all affirming behavioral and psychological origins for insomnia (averaging 10 of 18 indicators/patient), as well as averaging 2 or more psychiatric symptoms or conditions: depression (65.2%), anxiety (41.9%), traumatic exposure (35.1%), claustrophobia (29.7%), panic attacks (28.4%), and posttraumatic stress disorder (20.3%). All patients failed continuous or bilevel PAP and were manually titrated with auto-adjusting PAP modes (auto-bilevel and adaptive-servo ventilation). At 1-year follow-up, patients were compared through nonrandom assignment on the basis of a PAP compliance metric of > 20 h/wk (56 PAP users) versus < 20 h/wk (18 partial PAP users). RESULTS: PAP users showed significantly greater decreases in global insomnia severity (Hedges' g = 1.72) and sleep-onset insomnia (g = 2.07) compared to partial users (g = 1.04 and 0.91, respectively). Both global and sleep-onset insomnia severity decreased below moderate levels in PAP users compared to partial users whose outcomes persisted at moderately severe levels. CONCLUSIONS: In a nonrandomized controlled retrospective study, advanced PAP technology (both auto-bilevel and adaptive servo-ventilation) were associated with large decreases in insomnia severity for sleep-onset insomnia patients who strongly believed psychological factors caused their sleeplessness. PAP treatment of sleep-onset insomnia merits further investigation.

Adherence and Subthreshold Adherence in Sleep Apnea Subjects Receiving Positive Airway Pressure Therapy: A Retrospective Study Evaluating Differences in Adherence Versus Use.

BACKGROUND: Research on subthreshold compliance with positive airway pressure (PAP) therapy in sleep apnea patients may inform clinical sleep medicine practice. We retrospectively assessed compliant and subthreshold compliant sleep apnea subjects to test whether regular but fewer hours of PAP use would demonstrate clinically meaningful improvements and correlate with outcomes. METHODS: A chart review was conducted of 113 consecutive sleep apnea subjects, naive to treatment, who completed a titration study and filled a PAP therapy prescription. Objective data categorized subjects into 3 groups: compliant, subthreshold compliant, and minimal use. Outcome measures assessed changes in insomnia, sleepiness, and nocturia on average 7 months from PAP initiation. Correlation coefficients analyzed dose-response relationships between hours of use and changes in outcomes. RESULTS: Among 113 PAP attempters, 104 (92%) were current users. Among 93 users with objective data, regular (consistent) PAP users included 59 compliant and 21 subthreshold compliant, and 13 subjects were minimal users. Compliant users averaging 6.6 ± 1.3 h/night and 42.0 ± 12.1 h/week showed the largest outcome improvements (all P < .05) with moderate to large effects for insomnia (d = 0.94), sleepiness (d = 0.58), and nocturia (d = 0.56). Subthreshold users averaging 4.1 ± 0.7 h/night but only 18.0 ± 5.6 h/week showed a large effect for insomnia (d = 0.76, P = .03) and nonsignificant, small effects for sleepiness (d = 0.38) and nocturia (d = 0.22). Correlation coefficients showed a trend for decrease in insomnia (P = .08; r = .20) and a significant decrease in nocturia (P = .034; r = 0.25), each in association with hours of PAP use. CONCLUSIONS: In a clinical sample, 86% of sleep apnea subjects regularly used PAP, but adherence was 63%. Regular users showed clinical treatment effects and potential dose-response relationships, suggesting that the term use offers advantages over the term adherence. Currently, subthreshold compliance may not merit insurance coverage in many countries, an issue affecting many sleep apnea patients.