His research focuses on the evaluation of psychological treatments of somatic and psychiatric conditions, such as tinnitus, IBS, chronic pain, interpersonal violence, pathological gambling and depression and anxiety disorders. A particular interest is the application of advanced statistical models to test causal effects and mechanisms of change in treatment studies. Dr Hesser is an associate editorial board member of the leading CBT journal Behaviour Research and Therapy. He teaches courses in introductory and advanced quantitative methodology and he serves as a statistical advisor for the scientific journal Internet Interventions. He is also works part time as a clinical psychologist at Linköping university hospital.