Background: Insomnia and depression are clearly interrelated. Several studies showed that treating insomnia with cognitive behavioural therapy positively affects concurrent depressive symptoms. However, it is unclear what treatment component is responsible for the change in depressive symptoms.
Aims: To develop the evidence base we employed a case series design in which we administered a single component sleep restriction treatment to individuals with both insomnia and depressive symptoms.
Method: Seven patients were included, of whom six completed the intervention. Patients completed weekly assessments during the 4-week wait period and 6-week treatment phase.
Results: At the post-assessment, two out of six patients showed clinical improvement in depressive symptoms. All six patients showed clinically meaningful improvement at the 3-month follow-up assessment, and two patients had maintained gains at 6-month follow-up.
Conclusions: This case series study shows that, especially at 3-month follow-up, sleep restriction therapy is associated with clinically relevant treatment gains in patients with both insomnia and depressive symptoms.
Keywords: case series; depression; insomnia; sleep restriction treatment.