The direction of the relationship between symptoms of insomnia and psychiatric disorders in adolescents.

BACKGROUND: This study assessed the direction of the relationship between symptoms of insomnia disorder, depression, various anxiety disorders and obsessive compulsive disorder (OCD) in adolescents after controlling for age, gender, chronotype, and outcome variable at baseline. METHODS: Data was collected in eight high schools in Adelaide, South Australia, at two time-points approximately 6 months apart. The study was completed by 318 and 255 high school students at baseline and follow-up, respectively, aged 12-18 (M=14.96, SD=1.34) in grades 7-11 at baseline. Hierarchical regression analyses were used to assess each relationship, the first model controlling for age, gender and chronotype, and the second controlling for outcome variable at baseline. RESULTS: Insomnia symptoms predicted and were predicted by symptoms of each psychiatric disorder in model 1. In model 2, insomnia symptoms predicted symptoms of depression, and vice-versa. Symptoms of insomnia also predicted symptoms of separation anxiety disorder (SAD) once SAD, but not vice-versa, in model 2. Symptoms of obsessive compulsive disorder (OCD) and social phobia (SP) predicted symptoms of insomnia disorder in model 2, but not vice-versa. Insomnia symptoms were no longer related to symptoms of other anxiety disorders in model 2. LIMITATIONS: The use of self-report measures, and potential predisposing, precipitating, perpetuating or preventative factors were not assessed. CONCLUSIONS: Symptoms of insomnia disorder are bidirectionally related to depressive symptoms independent from baseline symptoms, and unidirectionally related to symptoms of OCD and SP where OCD and SP are independent risk-factors of the development of insomnia symptoms.

The independent relationships between insomnia, depression, subtypes of anxiety, and chronotype during adolescence.

OBJECTIVES: To investigate the independent effects of depression and subtypes of anxiety on insomnia, and vice versa, and the independent effect of chronotype on insomnia, depression, and subtypes of anxiety. METHODS: In all, 318 South Australian high school students from grades 7-11 (age range, 12-18years; mean, 14.97±1.34) participated in this cross-sectional study. Validated self-report questionnaires were used to assess insomnia, depression, subtypes of anxiety, and chronotype. RESULTS: After confounder variables were controlled, insomnia predicted depression and panic disorder (PD), whereas insomnia was predicted by depression and generalized anxiety disorder (GAD). Obsessive-compulsive disorder (OCD), separation anxiety (SAD), and social phobia (SP) were not significantly related to insomnia. Eveningness predicted the models in which depression and PD predicted insomnia and vice versa. Eveningness also predicted the models in which insomnia was predicted by OCD, SAD, and SP. CONCLUSIONS: Insomnia independently predicts depression and is predicted by depression and GAD, but not by other forms of anxiety. The independent prediction of insomnia on PD is unlikely to be clinically significant. Chronotype independently predicts and hence is a risk factor for insomnia and depression, but not subtypes of anxiety. Theoretical and clinical implications are discussed.

A Systematic Review Assessing Bidirectionality between Sleep Disturbances, Anxiety, and Depression.

STUDY OBJECTIVES: To investigate whether sleep disturbances are bidirectionally related to anxiety and depression, and thus identify potential risk factors for each problem. DESIGN: A systematic review was conducted on 9 studies (8 longitudinal, 1 retrospective) that assessed bidirectionality between a sleep disturbance, and anxiety or depression. Treatment studies were excluded, along with those solely based on clinical samples or cohorts at high risk of suffering from a sleep disturbance, anxiety and depression. Eligible studies were identified by searching PubMed, PsychINFO, Embase, and Scopus databases, and reference lists of eligible studies. Publication dates ranged from the beginning of each database to December 2011. MEASUREMENTS AND RESULTS: Syntheses of longitudinal studies suggested insomnia and sleep quality were bidirectionally related to anxiety and depression, and depression/anxiety, respectively. Childhood sleep problems significantly predicted higher levels of depression and a combined depression/anxiety variable, but not vice-versa. A one-way relationship was found where anxiety predicted excessive daytime sleepiness, but excessive daytime sleepiness was not associated with depression. CONCLUSIONS: Definitive conclusions regarding bidirectionality cannot be made for most sleep disturbances due to the small number and heterogeneity of cohort samples used across studies. Nevertheless, best available evidence suggests insomnia is bidirectionally related to anxiety and depression. Clinical and theoretical implications are discussed. CITATION: Alvaro PK; Roberts RM; Harris JK. A systematic review assessing bidirectionality between sleep disturbances, anxiety, and depression. SLEEP 2013;36(7):1059-1068.