The thesis consists of two volumes. Volume 1 comprises three chapters. The first, a systematic literature review of how positive relationships within families can support individuals experiencing psychosis. The second is a qualitative study investigating how families with one member with a first episode of psychosis have experienced their roles and relationships. The third chapter comprises a public domain briefing document which provides a plain language summary of the literature review and empirical paper. Volume 2 presents five Clinical Practice Reports (CPR). The first details a woman with a moderate learning disability who was experiencing anxiety, formulated from two psychological perspectives. The second is an evaluation of challenging behaviour guidelines for staff working in residential homes. The third report is an experimental design investigating the effectiveness of “Attentional Training” for a gentleman with health anxiety. The fourth report documents a case study of intervention with a male experiencing post-traumatic stress disorder. The fifth CPR is an abstract of a case presentation of a neuropsychological assessment of a young girl with a hypoxic-ischemic brain injury.