Digital Single-Session Cognitive Behavioural Therapy in Healthy Adults

The goal of this study is to learn if digital single-session cognitive behavioural therapy can treat mental health in adults. The main question it aims to answer is: * Does digital single-session cognitive behavioural therapy improve mental health in participants? Researchers will compare digital single-session cognitive behavioural therapy to a control intervention (digital memory task) to see if digital single-session cognitive behavioural therapy works to treat mental health. Participants will: * Complete either the digital single-session cognitive behavioural therapy or a digital memory task. * Complete some mental health questionnaires.