Appraisals of insomnia identity in a clinical sample

BACKGROUND

Insomnia identity, the conviction that one has insomnia, occurs independently of sleep quality or quantity, and is associated with numerous negative health outcomes. Little is known about factors influencing insomnia identity. This study planned to evaluate insomnia identity, perceived sleep experience, and sleep parameters.

METHOD

Individuals seeking treatment for an insomnia complaint reported demographics, insomnia identity ratings, and daily sleep diaries. Insomnia complaint and insomnia identity were independently crossed with sleep diary data yielding: complaining good (n = 10) and poor sleepers (n = 51), and good (n = 7) and poor sleepers (n = 40) with insomnia identity. Participants were additionally classified as with (n = 50) and without (n = 14) insomnia identity. Group differences and predictors of insomnia identity were assessed.

RESULTS

Complaining poor sleepers and poor sleepers with insomnia identity reported significantly poorer sleep ratings compared to their counterparts. Insomnia identity severity was predicted by worse sleep quality comparisons and increased helplessness. Analyses revealed poorer sleep parameters among those with an insomnia identity versus without.

DISCUSSION

Group differences may reflect variation in perceived sleep assessment and insomnia identity rating. Results further indicated that not all who complain of insomnia (and seek treatment) endorse insomnia identity. Implications of results and future study directions on insomnia identity are discussed.

Self-reported sleep complaints are associated with adverse health outcomes: cross-sectional analysis of the 2002/03 New Zealand Health Survey

OBJECTIVE

The aim was to investigate the prevalence of self-reported sleep complaints in New Zealand adults and determine the independent association of sleep complaints with adverse health outcomes.

DESIGN

We used 2002/03 New Zealand Health Survey data (n = 12,500 adults, ≥15 years). The prevalence of self-reported sleep complaints was estimated by ethnicity. The relationship between sleep complaints and mental health, physical health and health risk behaviors were investigated using multivariable logistic regression models.

RESULTS

The prevalence of each sleep complaint measure was highest for the indigenous Māori population (23.6% reported 'any' sleep complaint; 10.3% reported multiple sleep complaints). Reporting 'any' sleep complaint was associated with higher odds of poorer mental health, diagnosed high blood pressure, diagnosed diabetes, diagnosed heart disease, poor/fair self-rated health, obesity, current smoking, and hazardous drinking.

CONCLUSION

The higher prevalence of sleep complaints among Māori and the consistent association with poor health suggests a potential role for suboptimal sleep in ethnic health inequities.

Intraindividual sleep variability and its association with insomnia identity and poor sleep

OBJECTIVE

Insomnia identity refers to the conviction that one has insomnia, which can occur independently of poor sleep. Night-to-night variability in sleep (termed intraindividual variability [IIV]) may contribute to insomnia identity yet remain undetected via conventional mean analyses. This study compared sleep IIV across four subgroups: noncomplaining good sleepers (NG), complaining poor sleepers (CP), complaining good sleepers (CG), and noncomplaining poor sleepers (NP).

METHODS

This study analyzed 14 days of sleep diary data from 723 adults. Participants were classified according to presence/absence of a sleep complaint and presence/absence of poor sleep. A 2 × 2 multivariate analysis of covariance (MANCOVA) was performed to explore differences on five measures of sleep IIV: intraindividual standard deviation in total sleep time (iSD TST), sleep onset latency (iSD SOL), wake after sleep onset (iSD WASO), number of nightly awakenings (iSD NWAK), and sleep efficiency (iSD SE).

RESULTS

MANCOVA revealed significant main effects of poor sleep, sleep complaint, and their interaction on sleep IIV. Poor sleepers exhibited greater IIV across all sleep parameters compared to good sleepers. Similarly, individuals with a sleep complaint exhibited greater IIV compared to individuals with no complaint. The interaction revealed that iSD SOL was significantly greater among CP than NP, and iSD NWAK was significantly greater among CG than NG.

CONCLUSIONS

Greater night-to-night variability in specific sleep parameters was present among complaining versus noncomplaining sleepers in good and poor sleep subgroups. These findings suggest certain aspects of sleep consistency may be salient for treatment-seeking individuals based on their quantitative sleep status.