The current programme of research had four main aims. First, we hoped to extend existing work on experimentally induced distress with non-clinical samples of adult participants (male and female college students aged approximately 18-50 years), with a particular focus on finding an appropriate preparation that would lend itself to the exploration of brief therapeutic interventions. Second, we investigated the impact of techniques referred to as self as context in terms of ameliorating distress induced by the single-sentence preparation. Third, we compared effects of mindfulness and self as context techniques on distress reduction, and subsequently investigated effects of individual components of mindfulness. Finally, we explored the potential role of concepts derived from relational frame theory (RFT) in enhancing self as context techniques. Experiment 1 systematically compared a single-sentence preparation first proposed by Rachman, Shafran, Mitchell, Trant and Teachman (1996) to a multi-sentence distress induction procedure with a nonclinical sample of undergraduate participants (N = 64). The experiment was interested in determining which procedure was more effective in inducing distress (i.e. discomfort, anxiety and stress). Visual Analogue Scales (VASs) were used to measure changes in these dependent measures. We predicted that the multi-sentence preparation would generate greater distress. However, statistical analysis including a series of mixed between within analysis of variance (ANOVA’s) demonstrated that the preparations were equally effective in inducing emotional distress. The single-sentence distress induction procedure was employed again in Experiments 2-5 (N = 90). These studies also incorporated a number of brief analogue interventions derived from acceptance and commitment therapy (ACT). Put simply, the research question was: Would ACT interventions that targeted acceptance, defusion, values and contact with the present moment successfully ameliorate experimentally induced distress in a non-clinical sample of undergraduates. We also investigated whether each of these individual ACT components would be enhanced by a self as context technique. Similar to Experiment 1, VASs were used to measure any changes in discomfort, anxiety and stress as a result of the interventions. We hypothesised that the combined interventions (e.g. self-enhanced acceptance) would reduce distress more effectively. However, a series of mixed between within ANOVA’s demonstrated that all interventions, either stand alone components or combined with self as context, had little or no effect on levels of induced distress. In Experiments 6-8, we employed an alternative form of distress induction to previous experiments with a nonclinical sample of undergraduate participants (N = 80). In Experiment 6 we investigated the impact of mindfulness versus self as context techniques in reducing distress (i.e. discomfort, anxiety and stress) in a non-clinical sample as measured on the VASs (N = 30). We did not make any specific predictions about the outcomes, but were concerned with the possibility of differentiated outcomes based on the fact that self as context techniques encourage a focus on psychological events (i.e. thoughts), while mindfulness techniques encourage a focus on somatic events (i.e. the body). A series of mixed between within ANOVA’s demonstrated that both interventions were equally effective in reducing distress. In Experiment 7, we distinguished between two mindfulness-based exercises, physical mindfulness and verbal mindfulness, and thereafter investigated which of these would be more effective in reducing distress (e.g. discomfort) in a non-clinical sample (N = 26) of undergraduates (as measured by the VASs). Again, we refrained from making specific predictions about potentially different outcomes for the two mindfulness-based components because there are no such experimental comparisons available in the research literature to date. A series of mixed between within ANOVA’s demonstrated that both conditions reduced distress as measured via VASs and the difference in distress levels prior and subsequent to intervention was statistically significant. In Experiment 8, we turned our attention to an investigation of effects of sequence of mindfulness exercises and to the possibility that combining physical and verbal mindfulness exercises would enhance effects observed with either exercises individually. We hypothesised that the sequence which presented physical mindfulness followed by verbal mindfulness would show greater reductions in distress (as measured by the VASs) than the reverse because this is the format employed in most mindfulness-based therapeutic packages (e.g. Mindfulness-Based Stress Reduction). A series of mixed between within ANOVA’s demonstrated that this prediction was upheld with our non-clinical sample of (N = 24), undergraduates and although both conditions resulted in reduced scores on all measures of distress, the physical-verbal sequence demonstrated superiority. Experiments 9 and 10 employed the same distress induction procedure and a similar non-clinical sample of undergraduates as Experiments 6-8 in an effort to investigate the role of RFT in ACT exercises (N = 84). In particular, in Experiment 9 we investigated distinction and hierarchical relations when targeted specifically in a self as context exercise (N = 36). We hypothesised that the hierarchical self as context intervention would show superiority over the distinction self as context condition in terms of reductions in discomfort, anxiety and stress, based on previous research by Luciano et al. (2011). A series of mixed between-within ANOVA’s demonstrated results that were consistent with this prediction as the hierarchical intervention was the more effective in reducing distress as measured by the VASs. Experiment 10 attempted to explore this issue further using a different ACT exercise with undergraduate participants (N = 48). Participants were also exposed to a practice interval placed between two exposures to the distress induction task, to determine potentially lasting impacts of the interventions. A second aspect of the research examined the extent to which a focus on the self played a specific role in the outcomes described above. Accordingly, Experiment 10 compared interventions that focused on participants’ thoughts about a specific self-criticism (i.e. self-focused) versus interventions that focused on thoughts about an inanimate object (i.e. object-focused). We hypothesised that the self-based hierarchical intervention would be the most effective in terms of distress reduction (e.g. discomfort) because it aimed to target both self-specific content and hierarchical relations. This prediction was somewhat supported as statistical analysis demonstrated that both hierarchical conditions showed superiority in terms of distress reduction compared to both distinction conditions. Furthermore, both hierarchical conditions were associated with significantly less avoidance in the second exposure to the distress induction task. In the General Discussion the current thesis discusses the implications of the research and extending the existing literature on experimental distress induction procedures, ACT, mindfulness and RFT.