Mental health care is a major cost to all EU nations; and in many case, it results in additional costs to a country's economy due to the lost of productivity and concerns at the societal level. Cognitive Behaviour Therapy (CBT) is by far the treatment of choice for mental disorders such as depression, anxiety disorders, eating disorders, chronic insomnia, etc. We proposed an ontology-enhanced ubiquitous monitoring and treatment model for the purpose of assisting people to overcome the challenges of mental disorders. The research first presented a context ontology for mental disorders as the basis for gathering, formalizing and manipulating patients' data. Our work also implemented the proposed framework to facilitate online CBT, for treating Depression at the current stage, which combined talk/chat/message service, integrated Neurofeedback, and supported collaborative diagnosis. An online statistic report was also embeded in our system.