This thesis has been formed through clinical experience as a practitioner psychologist to develop original research that has direct clinical impact. It includes empirical research, a systematic review, and a reflective summary on the process of developing as an advanced researching practitioner. The empirical research included a large-scale custodial and community sample (N=1111) to establish psychological and modifiable factors of causation between adverse childhood experiences (ACE) and later harm inflicted on the self and others. As part of this empirical research, an integrated conceptualisation of shame and its multidimensional nature is proposed. As such the introduction includes a thorough background on this project's conceptualisation of shame. The empirical research highlights the importance of ACE, shame, and to a lesser extent self-compassion, in understanding the risk of harm to the self and others. It also indicates that shame and self-compassion are partial mediators in the relationship between ACE and harm. Three plausible Structural Equation Models are proposed to explain the relationship between ACE, shame, self-compassion and later harm to self and others, with harm to others separated into 'psychological and physical harm' and 'sexual harm'. Implications for theory and clinical practice are presented as well as future directions for research. The thesis also includes a systematic review, including a narrative review and meta-analysis, exploring whether psychological interventions reduce shame. Thirteen studies were included in this review and the results indicate that overall psychological interventions can be effective at reducing shame. Additionally, the review found that in the absence of psychological intervention, such as within control conditions, no reduction in shame was consistently observed. Finally, reflections of the process of developing from a practitioner who conducts occasional research to a more confident and competent advanced researching practitioner are presented
