Sleep quality, insomnia, and internalizing difficulties in adolescents: insights from a twin study

Objectives: There is a well-established association between poor sleep quality and internalising traits. This relationship has previously been studied using a twin design. However, when it comes to adolescence, there is a paucity of twin studies that have investigated this relationship, despite the importance of this developmental stage for both the development of poor sleep quality and internalising symptoms. Additionally, anxiety sensitivity, which is commonly associated with poor sleep quality, has not been studied in this context. Our objective was to estimate genetic and environmental influences on the relationships between insomnia, poor sleep quality and internalising symptoms in adolescence.

Methods: Insomnia, poor sleep quality, depression, anxiety and anxiety sensitivity traits were measured in a sample of 5,111 twin pairs from the Twins Early Development Study, born between 1994 and 1996 (mean age 16.32y (SD=0.68)).

Results: A moderate proportion of the variance for the different variables (.29-.42) was explained by genetic factors. Associations between sleep and internalising variables were moderate (r = .34 - .46) and there was a large genetic overlap between these variables (rA= 0.51 – 0.73).

Conclusion: This study adds novel information by showing that there are large genetic correlations between sleep disturbances and internalising symptoms in adolescence.