The principle
Depression narrows life: less activity, less reward, lower mood, even less activity. Behavioural activation reverses the spiral by scheduling small, valued activities regardless of motivation, and letting mood follow behaviour rather than waiting for it.
How to start
List activities under three headings: routine (eat, shower, daylight), pleasure (small joys), and mastery (anything you finish). Pick one tiny item per category and put it on tomorrow's calendar with a specific time. Aim for consistency, not intensity.
What the evidence says
Multiple randomised trials and NICE guidance support behavioural activation as a first-line psychological treatment for depression, with effects comparable to full CBT for many people.