Changing the context surrounding patients treated in psychiatric wards is a great challenge, with barriers in terms of the organization, work culture and clinical skill. We propose a model to influence the ward context by adding psychological treatment in both individual form and by teaching inpatient staff how to use a simplified ACT model to inform their daily interactions with patients. We further discuss difficulties in the implementation of psychological treatment in inpatient milieus. Results from three empirical studies in a naturalistic setting in Sweden form the basis of a model describing how access to evidence-based psychological treatment might be increased using limited extra resources. Data suggest that 1) an average of two individual ACT sessions might lessen the need for future inpatient care for psychosis patients, 2) inpatients as well as staff members themselves might benefit from staff learning and using a simplified ACT model, and 3) staff find the ACT model useful both in terms of helping patients handle psychiatric symptoms and in terms of handling their own work-related stress.