Although mediums report a range of experiences that share some similarities with symptom checklists for persons with mental health problems, relatively little systematic research has been undertaken to characterise the mental health and personalities of practising mediums, and none has been conducted in the UK. Previous research in other countries suggests that dissociation, fantasy-proneness and boundary-thinness might distinguish mediums from those who share a similar belief system but do not report mediumistic experiences. To address this, standardised measures were selected and combined in a questionnaire that was distributed to a sample of mediums and non-mediums as part of a nationwide survey. Mediums (N=80) scored significantly higher than non-mediums (N=79) on psychological wellbeing (p < .001), had lower psychological distress (p < .001), higher extraversion (p < .05), higher neuroticism (p < .001), and higher openness to experience (p < .01). No significant differences were found on dissociation, boundary-thinness, fantasy-proneness, conscientiousness or agreeableness. Results suggest that mediumship is not associated with a high level of dissociative experiences or pathology. Findings are discussed in relation to previous research, which proposes that the mediumship role may serve a therapeutic function for both mediums and those who consult them. The survey also included an open-ended Mediumship Activity Questionnaire (MAQ), which was designed to map the range and incidence of mediums' experiences. A content analysis of responses found mediums reported childhood anomalous experiences, family experiences and socialization as contributing factors in the development of their ability. Findings also increased our understanding of the process and nature of mediumship, and the spirit guide phenomenon. However, in order to explore the phenomenology of mediumship, it was clear that an approach would be necessary that could capture the "lived experience" of mediums. Thus, in-depth semi-structured interviews were conducted with ten mediums to explore their understanding of the mediumship process and were analysed using interpretative phenomenological analysis (IPA; Smith, 1996). Six superordinate themes were identified that illuminate key aspects of the mediumship phenomena, such as the various pathways to mediumship and how mediumistic experiences are interpreted and incorporated into a personal experiential framework: "A search for meaning: Normalisation of mediumship", "Progression of mediumship", "Relationship with spirit", "Spirit guides as transcendental", "Explanatory systems of mediumship", and "Mediumship as counselling", One of the main conclusions of this study was that the pathways to mediumship are embedded in a cultural context that provides an important environment in which mediumistic experiences are normalised and validated. Findings are discussed in relation to their clinical implications, in particular the need for mental health professionals to be aware of alternate models and beliefs.