Trajectories and associations between depression and physical activity in patients with cardiovascular disease during...

There is a lack of knowledge about internet-based cognitive behavioural therapy in patients with cardiovascular disease, and its effects on depressive symptoms and physical activity.

To examine trajectories of depressive symptoms and physical activity, and to explore if these trajectories are linked with the delivery of internet-based cognitive behavioural therapy.

A secondary-analysis of data collected in a randomised controlled trial that evaluated the effects of a 9-week internet-based cognitive behavioural therapy programme compared to an online discussion forum on depressive symptoms in cardiovascular disease patients. Data were collected at baseline, once weekly during the 9-week intervention period and at the 9-week follow-up. The Montgomery Åsberg depression rating scale - self-rating (MADRS-S) was used to measure depressive symptoms. Two modified items from the physical activity questionnaire measuring frequency and length of physical activity were merged to form a physical activity factor.

After 2 weeks the internet-based cognitive behavioural therapy group had a temporary worsening in depressive symptoms. At 9-week follow-up, depressive symptoms (P<0.001) and physical activity (P=0.02) had improved more in the internet-based cognitive behavioural therapy group. Only in the internet-based cognitive behavioural therapy group, was a significant correlation (r=-0.39, P=0.002) between changes in depressive symptoms and changes in physical activity found. Structural equation analyses revealed that internet-based cognitive behavioural therapy decreased depressive symptoms, and that a decrease in depression, in turn, resulted in an increase in physical activity.

Internet-based cognitive behavioural therapy was more effective than an online discussion forum to decrease depressive symptoms and increase physical activity. Importantly, a decrease in depressive symptoms needs to precede an increase in physical activity.