Individuals with gastrointestinal (GI) conditions often experience poor mental health and low QoL. However, research has seldom investigated the impact of Bile Acid Malabsorption (BAM) and Bile Acid Diarrhoea (BAD), specific GI conditions, on these outcomes. This thesis aimed to understand the impact of BAM / BAD on mental health and wellbeing. Part one of this portfolio presents a qualitative empirical paper that investigated the lived experience of those with the condition. It employed a photovoice methodology and was analysed using interpretative phenomenological analysis (IPA). The findings suggest that several aspects of the condition can impact upon wellbeing, namely the diagnostic process, the GI symptoms, and the need to manage a stigmatised identity. Part two presents a quantitative empirical paper that demonstrated the high prevalence of anxiety, depression and low quality of life in those with BAM / BAD. The findings also suggest that greater GI symptom severity is associated with greater anxiety and depression, alongside poorer quality of life in this population. Greater diarrhoea severity was shown to predict greater anxiety symptoms, whilst greater diarrhoea and indigestion severity predicted greater depression symptoms.