Background: The SWIS sleep training for university students showed promising results regarding subjective and objective sleep parameters. As sleep disorders and impaired sleep quality are closely related to various aspects of mental health, the current study examines the effects of the SWIS sleep training on mental health in university students.
Methods: Fifty six university students (M = 25.84, SD = 5.06) participated in the study, 68% were women. Forty one were randomly assigned to the SWIS treatment (pre-post-follow-up), 15 to a Waiting List Control condition (WLC, pre-post). Besides sleep-related measures, the students completed four online questionnaires measuring mental health, quality of life and stress coping strategies. Effect sizes for the pre-post data were compared between the conditions, long-term effects were calculated with repeated measures ANOVA or Friedman ANOVA. Long-term clinical changes were analyzed with the Reliable Change Index (RCI).
Results: The pre-post comparisons between SWIS and WLC revealed lower depression scores in both conditions, a better physical state in the SWIS condition and less maladaptive stress coping strategies in the WLC students. The long-term results of SWIS provided significant improvements regarding the students' somatic complaints, reduced anxiety, an improved physical state and a better quality of life with moderate to large effect sizes. Most of the significant improvements occurred between pre- and follow-up measurement. These statistically significant results were also reflected in clinically significant changes from pre- to follow-up-test.
Conclusions: SWIS and WLC condition both improved in two mental health variables immediately after the training. These findings may be explained by unspecific treatment expectation effects in the WLC. Interestingly, most mental health outcomes showed significant improvements after 3 months, but not immediately after the training. These positive long-term effects of the SWIS training on mental health indicate that the transfer of strategies might simply need more time to affect the students' mental health.
Trial registration: The current study was retrospectively registered at German Clinical Trials Register (ID: DRKS00014338 , registration date: 20.04.2018, enrolment of first participant: 14.04.2015).
Keywords: CBT-I; HT-I; Mental health; Quality of life; Sleep; Stress coping strategies.