Associations of subjective sleep quality with depression score, anxiety, physical symptoms and sleep onset latency in students.

OBJECTIVE: Sleep quality is strongly associated with parameters of mental and physical health and therefore a major public health issue. We wanted to evaluate this association in young and healthy students by a survey. Further, we aimed to detect the relevance of sleep onset latency and sleep duration for sleep quality.
METHODS: A group of young nursing and technical students was surveyed (N = 196) with the objective to measure subjective sleep quality, sleep onset latency, sleep duration, depression score, physical symptoms, trait-anxiety, and pathological eating behaviours.
RESULTS: Subjective sleep quality was strongly negative correlated with depression score (Pearson's r = -0.57), physical symptoms (r = -0.51) and trait-anxiety (r = -0.54) (p < 0.001 for all three). Subjective sleep quality's association with sleep onset latency was stronger than with sleep duration. Further, high depression score (odds ratio OR = 3.90; 95% confidence interval CI = 1.88-8.06) and long sleep onset latency (OR = 3.56; 95% CI = 1.65-7.69) were the best predictors of poor subjective sleep quality.
CONCLUSIONS: This study supports evidence that links physical and mental symptoms with poor sleep quality. Especially important is the fact that we found this connection in young and basically healthy adults. Taking into account that poor sleep quality has major negative long term impact on health, prevention programmes should focus especially on the association between depressive symptoms and subjective sleep quality that is significantly influenced by sleep onset latency.