Understanding and treating persecutory delusions: an interventionist-causal model approach

Paranoia denotes the fear that others intend to cause you harm. Like other psychiatric problems such as fears and phobias, there is a spectrum of severity of paranoia. It occurs most dramatically as delusions of persecution, but is related to suspicious thoughts that occur in 10-20% of the general population. There is a pressing need to develop better treatment. One way to achieve this is to draw upon knowledge of the causes of the problem. If a potential factor is causal, then by deliberately increasing or decreasing it there will be an effect on paranoia. In a unique programme, four studies will be carried out that take such an approach to paranoia. Manipulationist studies provide techniques that can be incorporated into treatments; this has been particularly demonstrated for anxiety disorders and the aim is to emulate this for paranoia. The final study will bring together all the applicant‘s work in a test of a new treatment package for persecutory delusions. Particular use will be made of virtual reality social environments, which provide an excellent means of studying and potentially treating paranoia. Importantly, new information on the effects of cannabis, the most commonly used illicit substance, will also be gained.