About 15% of the population have health problems due to arthritis and other associated conditions. The most common type of arthritis is osteoarthritis. The main reason why people with osteoarthritis go to see a doctor is pain. Pain is also the main reason why people with osteoarthritis lose their mobility. However the type of treatments available for people with osteoarthritis are very limited. Our research group has carried out studies that have shown that pain from osteoarthritis has an emotional effect on the brain that affects how pain is felt. This emotional effect could make a big difference to how patients respond to treatment or surgery. By reducing the effects of these emotions we could reduce how unpleasant the pain feels. This could also help to keep more people mobile. Our research aims to investigate how emotions such as anxiety and distress which affects how we feel pain, are altered by the natural painkillers made by the brain (opiates). We would like to approach people with osteoarthritis and ask them to take part in our study. Specifically, we would like to test a variety of people with different levels of anxiety and distress. We will make use of techniques that can produce images of the brain to measure the naturally occurring brain opiates, and how they affect how we expect (anticipate) and feel (give attention to) pain. These studies will help us explain how different people experience pain and why they respond differently to treatments. In the long term, they will also help us understand how the brains own painkillers work, and how we can improve on existing treatments for pain from osteoarthritis and also develop new therapies.