Background. Persecutory delusions are a common psychiatric symptom, affecting between 50 and 90% of those with psychosis.T hey are associatedw ith high levels of distress, social isolation and hospitalisation. Psychological theories of persecutory delusions have been developed in order to inform the care of this distressing symptom. Objectives. The current thesis has two aims. The literature review aims to evaluate two current psychological models of persecutory delusions, namely Daniel Freeman's model, which suggests that anxiety plays a direct causal role in persecutoryb eliefs, and Richard Bentall's model, which suggeststh at persecutory delusionsa re a defencea gainstl ow self-esteema nd depressionT. he researchp roject aimedt o finther investigateR ichardB entall's model by looking at patternso f selfesteem in two different types of persecutory delusion: poor me delusions, in which the individual feels that their persecution is not deserved; and bad me delusions, in which the individual feels that their persecution is deserved. Methods. The literature review comprises a comprehensive review of the literature looking at anxiety, self-esteem and depression in those with persecutory delusions. The research project used a combination of self-report questionnaires and a computer task to measure self-esteem in those with persecutory delusions. Findings. The literaturer eview outlinesh igh levels of anxiety,d epressiona nd low self-esteemin thosew ith persecutoryd elusions.L ittle evidenceis found to support Freeman's model of persecutory delusions. Some initial evidence however is found in support of a revised version of Bentall's model. The research project meanwhile found patterns of self-esteem in poor me and bad me delusions that were consistent with Bentall's revised model. Conclusions. The current thesis outlines support for Bentall's revised model of persecutoryd elusionsT. he thesisa lso outlinesn eedf or further researchin a number of areas.