Psychology Theses

Mental health concerns affect approximately 20% of adolescents worldwide, many of which can be linked to one’s sense of self. However, many psychological accounts of self have been shown to be poorly defined and lacking in strong theoretical foundations. The present thesis investigates the relationship between the self and adolescent mental health using evidence from Contextual Behavioural Science (CBS), which offers a coherent theory of self and identifies empirically testable units. Overall this body of research aims to empirically examine the theoretical assumptions of the CBS account of self at multiple levels of analysis and test the practical application of this with an adolescent population, while addressing issues identified across previous investigations. Study 1 tested the ability of a model of the three senses of self (self-as-content; self-as-process; self-as-context) to predict overall mental health in adolescents. A significant model emerged with all three predictor variables contributing significantly. Study 2, tested a clinical application of this theory through a brief school based intervention, targeting the development of a healthy sense of self as articulated by CBS. Study 2 results revealed no significant improvements following this intervention, compared to a theory of mind intervention and a no intervention control group. Study 3 examined these senses of self and other relevant behaviours (e.g. relating to others) in samples of adolescent textual responses using a qualitative behavioural measure. Consistent with Study 1, higher self-as-process was related to lower depression and lower anxiety for female participants, while lower rigid self-as-content was related to higher well being. Due to insufficient occurrences of self-as-context this relationship could not be examined reliably. Results also showed how one relates to others and ability to identify emotions have important implications for mental health, well-being, and psychological flexibility. Finally, study 4 involved a fine-grained investigation into the 2 types of self-as-context (distinction and hierarchy) at a naturally occurring level in a sample of older adolescents. Study results showed that self-as-hierarchy was significantly predictive of lower stress and depression, and that self-as-distinction was not predictive of mental health. Psychological flexibility was not found to mediate this relationship. Overall these findings make a unique and important contribution to the CBS literature. Findings are discussed in terms of theoretical and practical implications for how this body of evidence may serve to guide future empirical work