This thesis explores the mental health care experiences of lesbians and gay men when they are 'coming out'. It looks at how lesbians and gay men negotiate their sexual identities in mental health care contexts in which they have to manage the institutional homophobia and heterosexism embedded in the practice of nurses and other mental health care professionals. It is a qualitative study in which 48 lesbians and gay men, aged 17-55, participated in in-depth face to face interviews about their health care experiences. Innovative sampling approaches were used which reduced the sampling bias common in studies of hidden populations, and studies of lesbians and gay men in particular. Such sampling bias relates to social class, educational achievement, age, ethnicity and lesbian/gay community attachment. The data were analysed using a material-discursive approach which straddled epistemological divides in an attempt to side-step and overturn the dualisms which not only construct experiences but also limit out ability to conduct research into experience. The analysis was a bricolage using Interpretative Phenomenological Analysis, Positioning Theory and some deconstructive techniques. This allowed an engagement with both the material aspects of experience which were more readily articulated and the discursive aspects of experience which were often in the realm of the ineffable. The analysis permitted an understanding of the ways that lesbians and gay men are silenced and pathologised in their mental health care encounters, how they resist pathologisation and erasure, and how such resistance restricts access to care. Recommendations are made about how nursing and health care can be made more accessible to lesbians and gay men with mental health issues relating to their sexual identity, through depathologising sexual identities and through questioning the usefulness of the concept of individualised patient care; this approach does not lead inevitably to cultural competence and can reinscribe oppression through erasure.