Objectives: Research examining the relationship between social support and longterm mental illness has, on the whole, failed to address the complexity of the processes involved in receiving support from relationships. As a result, few clinical implications have arisen from the research. The aim of this study was to gain a more detailed understanding about the nature and complexity of the factors that make it difficult for people with long-term mental health problems to form relationships with others and to utilise the social support that is potentially available. The study recruited participants who were suffering from schizophrenia or depression. The comparative element of the design aimed to provide an increased understanding of how the psychiatric disorders impacted on people’s perceptions of their relationships, and how their relationships impacted on their emotional difficulties. Design: The study employed a qualitative research paradigm using a grounded theory methodology. Method: Two groups of participants were sought. One contained participants suffering from the symptoms of schizophrenia but not depression (the S group). The other contained participants suffering from severe unipolar depression (the D group). Face to face interviews were conducted using semi-structured interview schedules. The interviews aimed to develop a greater insight into users’ perceptions of their past and current relationships, their beliefs about what friends are for and the way they form friendships, the types of interpersonal problems experienced, perceived contributory factors to these interpersonal difficulties and the nature of the support desired to help overcome them. Results: Participant responses were analysed using aspects of the grounded theory method. Codes, categories and themes were generated from the data. Some themes were common to both groups. Others reflected important differences between them. Conclusions and Implications: A tentative theoretical framework was developed to account for the responses given by the two groups to the research questions. The data generated from the responses given by S group participants suggested they had difficulties in reflecting on their own or others’ mental states (i.e. difficulties in ‘reflective functioning’). This had important implications not only for the way the S group described and made sense of their relationships, and could account for some of the different themes generated by the two groups, but also pointed to several new intervention strategies (particularly strategies for overcoming this group’s social skills deficits). In contrast, the responses given by the D group suggested they had fewer difficulties in ‘reflective functioning’. Rather, it appeared that negative internal working models of caring relationships, formed from earlier experiences in their family, had resulted in a deep suspicion of close relationships and a continued anticipation of betrayal and rejection. This theory also accounted for some of the different themes that emerged between the two groups. It also pointed to intervention strategies for the D group. These theories have been incorporated into, and contrasted with, existing theory and research developments. Hypothesised developmental frameworks have been proposed to account for the data. Methodological and conceptual issues in the research have also been addressed and suggestions made for future research.