<p>Parent-child conversations about past experiences—reminiscing—are key in children’s growing emotional competency and their psychological well-being (Salmon & Reese, 2016). Very little research, however, has investigated the relationship between parent-adolescent reminiscing conversations and adolescent psychological adjustment, which is particularly important because adolescence is a period of heightened risk for the development of rumination and internalising disorders, especially anxiety and depression (Miller-Slough & Dunsmore, 2016). This thesis extended the literature on reminiscing in three ways. First, we examined different qualities of mother-adolescent reminiscing and their relationships to psychological outcomes during the period of middle adolescence. Second, we investigated the associations between mother-adolescent reminiscing qualities and youth rumination and internalising symptoms (anxiety and depression), cross-sectionally and longitudinally to help disentangle the direction of the associations. Finally, we applied dyadic methods of coding and statistical analyses in a novel approach that modelled the transactional nature of reminiscing conversations and their associations with youth psychological outcomes. In Study 1 we tested the discriminant and convergent validity of a dyadic coding scheme, for use on parent-adolescent conversations about past events. The aim of Study 1 was to establish the methodological foundations for examining parent-adolescent reminiscing conversations in a way that lends itself to dyadic analysis. To do this, two coding schemes (a traditional reminiscing scheme and a dyadic scheme) were applied to a community sample of 67 mother-adolescent dyad and their conversations about a past shared conflict event. Consistent with our predictions, parent-adolescent reminiscing qualities that extended the conversation and promoted highly detailed narratives were correlated with supportive interpersonal processes that endorsed co-construction and collaboration during the discussion. In contrast, qualities that discontinued the conversation were correlated with unsupportive interpersonal processes that promoted avoidance/disengagement and repetitive problem engagement. Next, we applied the dyadic coding scheme to assess the transactional relationships between parent-adolescent reminiscing qualities and youth rumination and internalising symptoms. In Study 2 we tested the cross-sectional (Study 2a) and longitudinal (Study 2b) relationships between parent-adolescent reminiscing qualities and youth rumination, anxiety, and depression. Using the same sample of 67 mother-adolescent dyads in Study 1, transcripts of the past conflict discussions were coded dyadically for unsupportive and supportive mother and adolescent reminiscing qualities. Self-report measures of rumination, anxiety, and depression were also collected from mothers and adolescents, respectively. The adolescents then completed the same self-report measures at a follow-up time-point one year later. Overall, dyadic analyses found no significant associations between mother-adolescent reminiscing qualities and youth rumination or depression, cross-sectionally or longitudinally. We did, however, find a bi-directional relationship between unsupportive mother-adolescent reminiscing qualities and heightened anxiety symptoms cross-sectionally. The concurrent findings suggest that mothers and adolescents are mutually reinforcing youth anxiety symptoms, in part, through the promotion of emotional avoidance. Furthermore, exploratory moderation findings, indicated a significant buffering effect of youth engagement in supportive conversational qualities during reminiscing about past negative events with their mothers, and lower levels of youth anxiety over time. These findings have implications for practice and theory. First, in terms of clinical intervention, the research refines our understanding of interpersonal factors related to youth anxiety during middle adolescence, in particular the role of the parent-adolescent reminiscing conversations. Second, the current research highlights the importance of adopting interpersonal methods when studying parent-adolescent interactions as a way to accurately model and test the inherently interpersonal nature of reminiscing.</p>