Organised by the EPA Section on Prevention of Mental Disorders. Early intervention in psychosis has an already established role in reducing the duration of untreated psychosis, preventing or at least delaying psychosis onset, and relieving clinical high-risk (CHR) patients them from their presenting symptoms. However, as a thorough diagnosis is always the prerequisite of a good intervention, the accurate early detection of psychoses by their CHR states is a prerequisite for an early tailored intervention in psychosis. In this course we will therefore focus on the early detection. The course participants will learn and discuss: - the concept of early detection, the rationale for the clinical approach, and the existing evidence-base - to recognize potential early signs of psychosis and learn the basics of diagnosing CHR states using different instruments for their assessment - to discuss potential ethical dilemmas, - the main theoretical challenges and - common obstacles in early detection. The course is practical and interactive, and suitable for mental health professional of all levels of experience. The participants will be able to present cases and problems from their daily work. The knowledge and experience acquired in this course are relevant as basis for the EPA course on Early Intervention and applicable to all areas of mental health. After the course the participants shall be able to detect patients possibly at clinical high-risk for psychosis.