Research in clinical and nonclinical samples has linked hallucination-proneness to di ssociative tendencies (possibly reflecting a consequence of traumatic experiences), maladaptive metacognitive beliefs, and a perturbed capacity to discriminate between internal and external cognitive events (i.e. reality discrimination). The studies included in this doctoral dissertation u sed a number of research methods ( experimental, questionnaire, meta-analytic and experience sampling methodologies) to expand this research and resolve a number of methodological limitations of previous studies in this area. Part of this dissertation examined the specificity of the associations between hallucinations, dissociation, metacognitive beliefs and perturbed reality discrimination when controlling for the confounding effect of symptom dimensions that frequently covary with hallucination-proneness (e.g. paranoid ideation). In addition, this PhD thesis aimed to examine the alleged mediational role of dissociation in the re lations hip between childhood trauma and hallucinations, and to investigate the interplay between dissociation and the cognitive mechanisms be lieved to underlie hallucinatory experiences. The findings of the current studies suggest that hallucination-proneness is specifically related to reality discrimination abnormalities and dissociative tendenc ies, but not to maladaptive metacog nitive beliefs when the impact of comorbid symptoms is taken into account. In addition, the present findings support recent accounts in suggesting that the apparent association between childhood trauma and hallucinatory experiences may be explained in terms of dissociative processes. These finding have implications for the continued investigation of the psychological underpinnings of hallucinatory experiences, and may inform the development and implementation of specific psychological interventions for the treatment of auditory hallucinations.