Weiss, JonathanAlbaum, Carly Sarah2023-10-032023-10-032023-10-03https://hdl.handle.net/10315/41449Psychosocial interventions can be beneficial for addressing mental health challenges for some autistic youth, but a sizeable portion of youth who take part in mental health treatment do not demonstrate clinically meaningful improvement. Examining therapeutic process factors may provide insight as to why some youth benefit from treatment, while others do not. The current research aimed to evaluate the role of various therapeutic process factors in mental health treatment for autistic children and adolescents through two studies. The first study involved a systematic review and a narrative synthesis of the literature on how therapeutic process factors have been measured and the association with treatment outcome following psychosocial intervention addressing mental health challenges for autistic youth. Twenty-five studies met inclusion criteria. Process factors assessed across studies included relational factors; treatment expectations, readiness, and satisfaction; and treatment engagement from youth and their parents. Process-outcome associations were reported for a limited number of constructs. The second study examined indicators of child engagement in relation to treatment outcome for autistic children who participated in cognitive behaviour therapy for emotion regulation. Indicators of child engagement included observational ratings of in-session involvement, and therapist ratings of therapeutic alliance between therapist and child and homework completion. Each indicator of engagement was measured at early, middle, and late stages of therapy. After controlling for pre-treatment scores, in-session involvement significantly predicted some aspects of post-treatment emotion regulation, whereas therapeutic relationship and homework completion did not. This dissertation addresses key gaps in research on mental health treatment for autistic youth by providing a detailed summary on what is currently known about therapeutic process factors and process-outcome associations in psychotherapy, and offers original findings that highlight the importance of child in-session involvement for therapeutic success. Research should continue to focus on relatively well-examined factors, such as therapeutic alliance, and explore factors that are less understood, such as client beliefs about treatment and parent involvement. Clinicians working with autistic clients should actively strive to form therapeutic alliance with youth and parents, and support positive treatment engagement for the full duration of therapy to enhance the likelihood of successful outcomes.Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Clinical psychologyDevelopmental psychologyMental healthElectronic Thesis or Dissertation2023-10-03AutismMental healthYouthPsychotherapyTherapeutic factors