A new generation of interventions has begun to move towards principles of acceptance that deal with the context and function of psychological events. The aim of this paper is to analyse the effectiveness of a brief contextual behavioural intervention to improve the psychological well-being of secondary school students. This intervention represents a unified model with key processes based on contextual behavioural science, including Acceptance and Commitment Therapy (ACT) and Functional Analytic Psychotherapy (FAP). We conducted an intervention with 94 students (age range 17–19 years), randomly assigned to an experimental group (n = 50) or control group (n = 44). Participants took a pretest and post-test of distress, life satisfaction, psychological flexibility and mindfulness. The intervention consisted of three sessions of 1 h each. The results showed significant differences between the groups in distress and significant differences for the interaction (group × pre–post) in all the other variables. The intervention had greater benefits for girls than for boys. These results may provide a breakthrough, thus leading to a process of evidence-based therapies, which would be responsible for inducing psychological improvements in brief periods, in a population with an increasing risk of distress.
