Safety behaviors and dysfunctional beliefs about sleep: testing a cognitive model of the maintenance of insomnia

OBJECTIVE: Our aim was to determine if insomnia severity, dysfunctional beliefs about sleep, and depression predicted sleep-related safety behaviors. METHOD: Standard sleep-related measures (such as the Insomnia Severity Index; the Dysfunctional Beliefs About Sleep scale; the Depression, Anxiety, and Stress Scale; and the Sleep-Related Behaviors Questionnaire) were administered. Additionally, 14 days of sleep diary (Pittsburg Sleep Diary) data and actual use of sleep-related behaviors were collected. RESULTS: Regression analysis revealed that dysfunctional beliefs about sleep predicted sleep-related safety behaviors. Insomnia severity did not predict sleep-related safety behaviors. Depression accounted for the greatest amount of unique variance in the prediction of safety behaviors, followed by dysfunctional beliefs. Exploratory analysis revealed that participants with higher levels of depression used more sleep-related behaviors and reported greater dysfunctional beliefs about their sleep. CONCLUSION: The findings underlie the significant influence that dysfunctional beliefs have on individuals' behaviors. Moreover, the results suggest that depression may need to be considered as an explicit component of cognitive-behavioral models of insomnia.     

The impact of temperament and character on the efficacy of nonpharmacologic treatment of primary insomnia

Nonpharmacologic treatment, also known as cognitive behavioral treatment, is a first-line treatment of primary insomnia. We aimed to assess factors, including temperament and character, that were associated with responses to nonpharmacologic treatments of primary insomnia, that may assist physicians to recommend appropriate treatment. Outpatients diagnosed with psychophysiological insomnia (n = 99) were recruited between May 2009 and January 2010. Among 69 patients who consented to participate, 44 completed treatment and all assessment measures. In addition, 37 normal control subjects were also recruited. Baseline characteristics were assessed using the Temperament and Character Inventory, the Insomnia Severity Index, the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Dysfunctional Beliefs and Attitudes about Sleep scale, and the Hospital Anxiety and Depression Scale. After treatment, all assessment scales excluding the Temperament and Character Inventory were repeated. All patients received nonpharmacologic treatments, including sleep restriction, cognitive therapy, and sleep hygiene education. Novelty seeking, harm avoidance, reward dependence, cooperativeness, and self-transcendence scores were significantly different between normal controls and study subjects. Participants were divided into treatment responders (n = 23) and nonresponders (n = 21). Responders were significantly younger (50.3 ± 12.8 vs 58.7 ± 9.6 years, P = .02) and had significantly higher reward dependence scores (51.7 ± 5.9 vs 42.9 ± 6.9, P < .01) compared with nonresponders. The difference in reward dependence scores remained significant after controlling for other factors (odds ratio, 1.23; 95% confidence interval, 1.08-1.40; P = .01). Among personality dimensions, reward dependence was significantly associated with response to nonpharmacologic treatment in patients with primary insomnia.     

Psychological and behavioral factors in patients with comorbid obstructive sleep apnea and insomnia

Objective

Insomnia symptoms in patients with obstructive sleep apnea (OSA) are commonly assumed to be secondary to respiratory disturbances. Previous studies, however, showed that insomnia might persist after treatment for OSA. Higher levels of emotional disturbances were reported in OSA patients with insomnia than those without insomnia, which suggests that psychological factors may play an important role for their sleep difficulties. This study aimed to further explore sleep-related psychological/behavioral factors that may contribute to insomnia in OSA patients.

Methods

This study included 88 men, of which 33 had OSA (OSA group); 29, primary insomnia; (Insomnia group); and 26, both OSA and insomnia (OSA+Insomnia group). All subjects underwent polysomnography (PSG) overnight and completed a package of questionnaires, including the Insomnia Severity Index (ISI), Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), Sleep Hygiene Practice Scale (SHPS), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), and Pre-Sleep Arousal Scale (PSAS).

Results

The OSA+Insomnia and Insomnia groups had significantly more dysfunctional sleep beliefs, more arousal-inducing sleep-related behaviors, and higher levels of pre-sleep arousal, anxiety, and depression than did the OSA group. The respiratory indices and arousal index were higher for OSA and OSA+Insomnia groups than for the Insomnia group.

Conclusion

Although OSA patients with insomnia showed a similar degree of respiratory disturbances as patients with OSA only, their psychological and behavioral profiles resembled the features of primary insomnia patients. The results support the concept of comorbid insomnia and suggest the importance of evaluating and treating both physiological and psychological factors in these patients.     

Relationship between maladaptive cognitions about sleep and recovery in patients with borderline personality disorder

Borderline personality disorder (BPD) has been associated with maladaptive cognitive processes including dysfunctional attitudes and a negative attribution style. Comorbid insomnia affects the course of multiple psychiatric disorders, and has been associated with the absence of recovery from BPD. Because dysfunctional beliefs and attitudes are common among patients with insomnia, the purpose of this study was to evaluate the association between maladaptive sleep-related cognitions and recovery status (symptomatic remission plus good concurrent psychosocial functioning) in patients with BPD. Two hundred and twenty three BPD patients participating in the McLean Study of Adult Development (MSAD) were administered the Dysfunctional Beliefs and Attitudes about Sleep questionnaire (DBAS-16) as part of the 16-year follow-up wave. Maladaptive sleep cognitions were compared between recovered (n=105) and non-recovered (n=118) BPD participants, in analyses that adjusted for age, sex, depression, anxiety, and primary sleep disorders. Results demonstrated that non-recovered BPD patients had significantly more severe maladaptive sleep-related cognitions as measured by the overall DBAS-16 score. These results demonstrate an association between dysfunctional beliefs and attitudes about sleep and recovery status among BPD patients. Further research is warranted to evaluate treatments targeted towards maladaptive sleep-related cognitions, and their subsequent effects on the course of BPD.     

An investigation of a cognitive refocusing technique to improve sleep

Developing techniques designed to minimize arousing cognitions during the evening may be important to help improve the treatment of insomnia. This investigation assessed an intervention that focused exclusively on enhancing cognitive refocusing at sleep onset to change the content and style of presleep cognitions in order to improve sleep. Individuals with primary insomnia (N=10; 90% male, mean age=49.2, SD=12.6) attended four weekly individual meetings. Sleep quality (the Pittsburgh Sleep Quality Index), insomnia severity (the Insomnia Severity Index), sleep parameters based on one week of sleep diaries, and arousing thought content, were compared at baseline, posttreatment, and at a 1-month follow-up. Adherence was high, and participants showed good ability to engage in the procedure. Significant improvements in sleep quality, insomnia severity, sleep onset latency, total sleep time, and arousing thought content were revealed. Large effect sizes were observed on the majority of sleep variables at follow-up. Preliminary results were encouraging regarding a technique that targets the refocusing of thoughts during the evening in order to improve sleep. Further study regarding the efficacy of this procedure is warranted.     

Identifying the best sleep measure to screen clinical insomnia in a psychiatric population

BackgroundInsomnia symptoms are highly prevalent among patients with psychiatric disorders, and this mandates the need to identify the best self-administered sleep measure to screen for clinical insomnia among them.MethodsA total of 400 psychiatric outpatients completed the Pittsburgh Sleep Quality Index, Insomnia Severity Index (ISI), Epworth Sleepiness Scale, Flinders Fatigue Scale, Functional Outcomes of Sleep Questionnaire, and Dysfunctional Beliefs and Attitudes about Sleep Scale in a cross-sectional study. The sensitivity, specificity, positive, and negative predictive values of these six sleep scales were assessed and compared in relation to both ICD-10 and DSM-5 insomnia disorder status established using the interviewer-administered Brief Insomnia Questionnaire.ResultsReceiver operator characteristic curves with the area under the curve (AUC) revealed the ISI to be the most accurate measure to discriminate cases and non-cases on both ICD-10 (AUC = 0.88, 95% CI = 0.84–0.92) and DSM-5 (AUC = 0.82, 95% CI = 0.78–0.86) criteria with “good” accuracy. The cut-off scores of ≥14 and ≥ 11 for the ISI provided optimal sensitivity and specificity for the detection of ICD-10 and DSM-5 insomnia, respectively.DiscussionWith the new calling from DSM-5 to treat sleep symptoms in the presence of a co-existing mental condition, early detection of psychiatric patients with clinically significantly insomnia using a simple but accurate self-report sleep measure becomes important. Our study suggests that the ISI could be used as a potential screening tool for comorbid insomnia disorder in patients with mental disorders.     

New assessment tools that measure sleep vital signs: the SleepMed Insomnia Index and the Sleep Matrix

Insomnia is the leading sleep disorder in the US; however, diagnosis is often problematic. This pilot study assessed the clinical value of a novel diagnostic insomnia questionnaire. The SleepMed Insomnia Index (SMI) was administered to 543 consecutive patients and 50 normal control subjects during a pilot study. Mean SMI scores were assessed based on subsequent sleep-related diagnoses. The SMI scores for patients with sleep-related disorders were significantly higher than those for the control group (p < 0.001) and highest for the 90 patients comprising the insomnia group. Analysis of the SMI scores from the 90 insomnia patients indicates a high degree of reliability (Cronbach’s alpha: 0.7). These data support our clinical experience with this diagnostic tool which indicates a strong likelihood of disrupted nighttime sleep in patients with high SMI scores. Following further validation, the SMI may prove to be a valuable tool for evaluating sleep disorders, specifically as an aid in the diagnosis of insomnia. The Sleep Matrix is a visual tool that quantifies a sleep complaint by combining scores from the Epworth Sleepiness Scale (ESS) and the SMI. The SMI measures an insomnia component while the ESS is an accepted measure of daytime sleepiness. The Sleep Matrix visually displays the complexity of the sleep complaint in an effort to differentiate insomnia with differing etiologies from other sleep disorders and measure treatment outcomes. To pilot test the Sleep Matrix, the tool was administered to 90 patients with insomnia and to 22 normal controls. Plots from the insomnia patients were concentrated into the “insomnia zone” while scores from the normal controls were located in the “normal zone” located in the lower left quadrant. Additional research using the Sleep Matrix could provide data that the tool could be utilized to visually aid the clinician in the diagnosis of unknown sleep complaints.     

Frequency of insomnia report in patients with obstructive sleep apnoea hypopnea syndrome (OSAHS)

BACKGROUND AND PURPOSE: Insomnia and Obstructive Sleep Apnoea Hypopnea Syndrome (OSAHS) are the two most common sleep disorders, and both have significant associated health costs. Despite this, relatively little is known about the prevalence or impact of insomnia in those with OSAHS, although a recent study suggested there may be substantial comorbidity between these disorders [Chest 120 (2001) 1923-9]. The primary aim of this study was to further explore the prevalence of insomnia in OSAHS. A secondary aim was to assess the effect of factors that may impact on both conditions, including mood and sleep-beliefs. PATIENTS AND METHODS: Consecutive patients referred to an accredited Sleep Investigations Unit [n = 105] completed a brief standardized battery of validated questionnaires assessing sleep-related variables and mood. RESULTS: Results showed a high rate of prevalence of clinical insomnia in this OSAHS population, and a strong positive correlation between OSAHS and insomnia symptom severity. Further, OSAHS patients with comorbid insomnia had increased levels of depression, anxiety and stress compared to patients with OSAHS-only, and both patient groups reported similar and significant levels of dysfunctional beliefs about sleep. Findings in relation to habitual sleep, assessed using subjective (diary) and objective criteria (polysomnogram), were mixed but generally showed greater sleep disturbance among those with OSAHS-insomnia compared to those with OSAHS-only. CONCLUSIONS: Overall these findings suggest that comorbidity of insomnia in OSAHS patients may lead to increased OSAHS severity and that patients with both conditions may experience more symptoms relating to depression, anxiety and stress. These findings underscore the need for insomnia assessment and management services, even in clinics that primarily service patients with OSAHS.     

Comparison of impact of insomnia on depression and quality of life in restless legs syndrome/Willis–Ekbom disease and primary insomnia patients

BackgroundAlthough insomnia is common among people with restless legs syndrome (RLS), its impact on the daily suffering of those with RLS remains unclear. This study aimed to compare the differential impact of clinical insomnia on depression and quality of life (QoL) among people with RLS, primary insomnia, and healthy controls.MethodsA total of 148 people with RLS, 115 with primary insomnia, and 117 healthy controls were enrolled into this cross-sectional study. Participants completed sleep, depression, and QoL questionnaires. Clinical insomnia was defined as Korean version of the Insomnia Severity Index (K-ISI) ≥ 15. Correlation coefficients between sleep measures and both depression and QoL were calculated. Multivariate regression was used to identify the clinical factors that were most closely associated with depression and QoL among people with RLS and primary insomnia.ResultsParticipants with RLS had insomnia and sleep quality at intermediate levels between the healthy controls and primary insomnia subjects, but those with clinical insomnia had equivalent depression and QoL scores regardless of RLS diagnosis. Insomnia severity correlated with depression and QoL in RLS and primary insomnia. Multivariate regression, however, revealed that RLS severity was the most overall predictive factor for depression and QoL among those with RLS. Insomnia severity was the strongest predictor in primary insomnia.ConclusionInsomnia was more closely associated with depression and QoL among people with primary insomnia than those with RLS, but clinical insomnia may have a significant impact in RLS as well. Future RLS studies should account for sleep quality in addition to RLS symptom severity when investigating mood and QoL.     

The role of dysfunctional beliefs and attitudes in late-life insomnia

OBJECTIVES: This study examined the role of individual and combined sleep-related dysfunctional beliefs in late-life insomnia. METHODS: Older adults who responded to an advertisement in a magazine took part in a cross-sectional survey (N=382). Respondents completed self-report measures of dysfunctional beliefs about sleep (Dysfunctional Beliefs and Attitudes to Sleep Scale) as well as measures of their current sleep patterns. RESULTS: Overall, people with insomnia (PWI) endorsed more extreme ratings of dysfunctional beliefs than "good sleepers" did. However, some sleep-related dysfunctional beliefs did not discriminate PWIs from good sleepers nor were they related to experiencing a longer duration of insomnia. CONCLUSION: This article demonstrates that not all sleep-related dysfunctional beliefs are related to reporting insomnia and that some are not related to a longer reported duration of insomnia, possibly changing through personal experience. These preliminary results may have implications for tailoring the cognitive aspects of psychoeducational programmes for people with late-life insomnia.     

Are dysfunctional attitudes and beliefs about sleep unique to primary insomnia?

ObjectiveDysfunctional thinking about sleep is a central aspect in the perpetuation of primary insomnia and a target symptom of cognitive behavioral therapy for insomnia (CBT-I). Insomnia symptoms also occur in other sleep disorders, but it is not known to what extent it is related to dysfunctional thinking about sleep.MethodsThe Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS) was administered to inpatients at a sleep center. The following groups were included: 34 patients with primary insomnia (PI), 30 patients with sleep apnea syndrome (SAS), 31 patients with restless legs syndrome (RLS), 26 patients with SAS comorbid with RLS (SAS + RLS), and 24 patients with idiopathic hypersomnia or narcolepsy. Eighty-four healthy subjects served as a control group. The DBAS scores were compared across the different sleep disorders and correlated with polysomnographic (PSG) variables, subjective sleep parameters, scores of the Beck Depression Inventory (BDI), and the Regensburg Insomnia Scale (RIS; measuring psychological symptoms of insomnia).ResultsCompared to healthy controls, DBAS scores were increased in PI, RLS and RLS + SAS. There was a low correlation between DBAS scores and PSG variables, moderate correlations between DBAS and subjective sleep parameters and BDI scores (r = 0.528), and a high correlation between DBAS and the RIS score (r = 0.603).ConclusionThe observation of increased DBAS scores in other sleep disorders besides primary insomnia underscores the usefulness of a broadened diagnostic procedure and suggests that CBT-I modules may be a complementary treatment tool for these disorders.     

Personality and Sleep Evaluation of Patients with Tinnitus in Japan

In Japan, there have been no examinations of tinnitus with respect to personality traits, and only a few studies have investigated sleep disorders in tinnitus. Understanding the association between these can aid in selecting and developing effective treatment options for patients with tinnitus. This study aimed to clarify the relationship between tinnitus severity, personality, and sleep disorders, in patients with chronic tinnitus in Japan. We retrospectively evaluated the personality factors of 56 patients presenting with tinnitus using the NEO Five-Factor Inventory (NEO-FFI), which examines five personality characteristics, including Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness. We evaluated tinnitus severity, sleep disorders, depression, and anxiety using the Tinnitus Handicap Inventory, Pittsburgh Sleep Quality Index (PSQI), Self-Rating Depression Scale, and State-Trait Anxiety Inventory, respectively. Neuroticism and tinnitus severity were positively correlated (r?=?0.548, p?<?0.001). Sleep disorders were observed in 73.2% of patients; however, there was no correlation between the PSQI score and tinnitus severity or between PSQI score and scores of the five NEO-FFI items. Sleep disorders are frequently experienced by patients with chronic tinnitus, regardless of tinnitus severity or personality. Understanding the relationship between personality and tinnitus severity could lead to better management of tinnitus.

     

老年慢性失眠相关认知障碍的危险因素分析

目的探讨老年慢性失眠相关认知障碍的危险因素。方法回顾性筛选老年慢性失眠患者107例,根据蒙特利尔认知评估量表(Mo CA)评分将患者分为认知障碍组与非认知障碍组。比较两组患者一般临床资料、失眠严重程度指数(ISI)、匹兹堡睡眠质量量表(PSQI)评分、汉密顿抑郁量表(HAMD)、焦虑量表(HAMA)评分,睡眠观念态度量表(DBAS)评分等。采用多因素logistic回归分析探讨老年慢性失眠相关认知障碍的独立危险因素。结果多因素logistic回归分析显示,主观睡眠障碍(OR=16. 064,P=0. 003)、睡眠潜伏期(OR=10. 567,P=0. 032)、习惯性睡眠效率(OR=21. 697,P=0. 006)、睡眠紊乱(OR=24. 754,P=0. 008)是老年慢性失眠患者相关认知障碍的独立危险因素。结论主观睡眠质量差、睡眠潜伏期长、习惯性睡眠效率低、睡眠紊乱严重是老年慢性失眠患者罹患认知障碍的独立危险因素。     

An open trial of cognitive-behavioral treatment for insomnia comorbid with alcohol dependence

OBJECTIVE: We evaluated the efficacy of cognitive-behavioral treatment for insomnia in recovering alcoholic patients in an open pilot study. METHODS: Seven abstinent alcoholic patients (3 women, mean age 38.6+/-10.8 years) recruited from outpatient and residential treatment facilities met the Diagnostic and Statistic Manual of Mental Disorders - Fourth edition (DSM-IV) criteria for insomnia comorbid with alcohol dependence and participated in eight individual treatment sessions. Participants were free of other medical, psychiatric, and sleep disorders. Daily sleep diaries were completed beginning two weeks before treatment until two weeks after treatment. Measures of sleep, daytime functioning, and drinking were collected. RESULTS: Diary-rated sleep latency [F(2,10)=14.4, p<.001], wake after sleep onset [F(2,10)=7.7, p=.009], and sleep efficiency [F(2,10)=28.3, p<.001] improved as did patient-rated and clinician-rated Insomnia Severity Index (ISI) and the Dysfunctional Beliefs and Attitudes about Sleep - Short Form (DBAS-SF). Compared to pre-treatment, significant post-treatment improvements were found on scales measuring depression and anxiety symptoms, fatigue, and quality of life. No one relapsed to alcohol during treatment. CONCLUSIONS: Cognitive-behavioral insomnia therapy may benefit recovering alcoholics with mild to moderate insomnia by improving sleep and daytime functioning. Effects on relapse remain to be determined. Findings need to be interpreted cautiously due to the uncontrolled design and lack of follow-up assessments.     

Sleep disturbances are correlated with decreased morning awakening salivary cortisol

Morning and evening salivary cortisol levels were correlated with sleep parameters in 14 patients with primary insomnia and 15 healthy controls. Salivary cortisol was sampled immediately after awakening (T1), 15 min later (T2), and immediately before going to bed (T3) for 1 week at home. In parallel with this, subjects estimated parameters of sleep in a daily sleep log. Patients and controls were all non-smokers who did not differ regarding morning awakening time or bedtime. Cortisol after awakening was significantly decreased in primary insomnia. Salivary cortisol at the time of awakening correlated negatively with the subjective estimation of sleep quality, i.e. a low salivary cortisol level directly after awakening correlated with a higher frequency of nightly awakenings (r = -0.50), a diminished sleep quality (r = -0.34) and a decreased feeling of recovery after awakening (r = -0.35; all p < 0.05). Furthermore, awakening cortisol was negatively correlated with the Pittsburgh Sleep Quality Index (r = -0.43) and with a questionnaire on sleep-related cognitions with the subscales rumination in bed (r = -0.56 ) and focusing on sleep-related thoughts (r = -0.46; all p < 0.05).     

Correlates and prognostic relevance of sleep irregularity in inter-episode bipolar disorder

ObjectivesSleep–wake disturbances, such as sleep irregularity, are common in bipolar disorder. Early studies suggest that sleep irregularity is associated with mood symptoms in bipolar disorder, but little research has been conducted to identify other correlates of sleep irregularity. We investigated the relationship between sleep irregularity and sleep quality, social rhythms, eveningness, sleep-related cognitions and behaviors, and past and future mood episodes in 84 patients with inter-episode bipolar I or II disorder.MethodsThis is a retrospective and prospective, naturalistic follow-up study. The Expanded Consensus Sleep Diary, Pittsburgh Sleep Quality Index (PSQI), Social Rhythm Metric (SRM-II-5), Composite Scale of Morningness (CSM), Dysfunctional Beliefs and Attitudes About Sleep Scale (DBAS-16), and Sleep Hygiene Practice Scale (SHPS) were administered. The Square Successive Difference (SSD), derived from a week-long sleep diary, was used as an index of sleep irregularity. Multilevel modeling analysis, which adjusts for biases in parameter estimates, was used to minimize the impact of missing data. Bonferroni correction was performed to account for multiple testing.ResultsHigher SSD scores of sleep diary variables were significantly associated with higher PSQI, SRM-II-5, DBAS-16, and SHPS scores. Irregularity in total sleep time was related to more depressive episodes in the past 5 years (p = .002), while irregularity in wake after sleep onset predicted the onset of depressive episodes over the next 2 years (p = .002).ConclusionSleep irregularity was associated with poor sleep quality, irregular social rhythms, dysfunctional sleep-related cognitions and behaviors, and greater number of depressive episodes in bipolar disorder.     

Comparing and contrasting therapeutic effects of cognitive-behavior therapy for older adults suffering from insomnia with short and long objective sleep duration

Study objectivesThis study evaluated the efficacy of a brief group-based program of cognitive-behavior therapy for insomnia (CBTi) for older adults suffering from chronic insomnia with short objective sleep relative to those with long sleep duration.MethodNinety-one adults (male = 43, mean age = 63.34, standard deviation (SD) = 6.41) with sleep maintenance insomnia were selected from a community-based sample. The participants were classified as short sleepers (SS; <6 h total sleep time) or long sleepers (LS; ≥6 h total sleep time) based on one night of home-based polysomnography. Participants were randomly allocated to a 4-week, group-based treatment program of CBTi (N = 30 SS; N = 33 LS) or to a wait-list control condition (N = 9 SS, N = 19 LS). One-week sleep diaries, actigraphy, and a comprehensive battery of questionnaires were used to evaluate the efficacy of CBTi for those with short objective sleep relative to those with long sleep duration. Outcome measures were taken at pretreatment, posttreatment, and a 3-month follow-up.ResultsCBTi produced robust and durable improvements in quality of sleep, including reduced wake after sleep onset and improved sleep efficiency. Participants reported a reduction of scores on the Insomnia Severity Index, Flinders Fatigue Scale, Epworth Sleepiness Scale, Daytime Feeling and Functioning Scale, Sleep Anticipatory Anxiety Questionnaire, the Dysfunctional Beliefs and Attitudes about Sleep Scale, and gains on the Sleep Self-Efficacy Scale. All improvements were significant relative to their respective SS or LS wait-list group. The benefits of CBTi were comparable with those who had short and long objective sleep before the treatment.ConclusionsOlder adults suffering from chronic insomnia with short objective sleep received comparable therapeutic benefits following CBTi relative to those with long objective sleep duration.     

The Spanish version of the Insomnia Severity Index: a confirmatory factor analysis

ObjectiveTo examine the psychometric properties of the Spanish version of the Insomnia Severity Index (ISI) and to determine its factor structure with confirmatory factor analysis (CFA).MethodsSelf-reported information was collected from a sample of 500 adults (mean age 39.13 [standard deviation 15.85] years) drawn from a population of medical students and their social networks. Together with the ISI, a measure of the subjective severity of insomnia, subjects completed the Pittsburg Sleep Quality Index, the Epworth Sleepiness Scale, and the Profile of Mood States to study concurrent validity of the ISI. CFA was used to test alternative models to ascertain the factorial structure of the ISI.ResultsThe Spanish version of the ISI showed adequate indices of internal consistency (Cronbach’s α = 0.82). CFA showed that a three-factor structure provided a better fit to the data than one-factor and two-factor structures. The ISI was significantly correlated with poor sleep quality, fatigue, anxiety, and depression, and discriminated between good and poor sleepers.ConclusionsThe ISI is a reliable and valid instrument to assess the subjective severity of insomnia in Spanish-speaking populations. Its three-factor structure (i.e., night-time sleep difficulties, sleep dissatisfaction and daytime impact of insomnia) makes it a psychometrically robust and clinically useful measure.