A prominent need in the youth psychotherapy literature includes the examination of mechanisms of change within the context of "real world" clinical settings, where the practice of psychotherapy differs significantly from that in controlled clinical trials. In examining mechanisms of change in youth psychotherapy, variables related to parent functioning may be among the most important factors to consider in predicting and promoting good child outcomes. The purpose of the present study was to evaluate three important aspects of parent functioningpsychological symptom distress, interpersonal relations, and social role performance-as potential predictors of successful treatment outcomes in a traditional community outpatient treatment setting for children and adolescents. Further, this study examined whether parents indirectly benefited from their children receiving services, expanding our view on the scope and benefits inherent in youth psychotherapy. Parent Symptom Distress, Interpersonal Relations, and Social Role performance were measured using the domains of the Outcome Questionnaire 45 (OQ-45; Lambert et al., 2004), and youth treatment outcomes were measured using the parent and self-report versions of the Youth-Outcome Questionnaire (Y-OQ; Burlingame, Wells, Lambert, & Cox, 2004; Y-OQ-SR; Wells, Burlingame & Rose, 2003). Using Hierarchical Linear Modeling with this sample of 339 youth, aged 4-17 and their parents, this study examined the relationship between these parent domains and youth progress in therapy. Results revealed that parent Symptom Distress and Social Role performance improved significantly over the course of youth treatment. Further, Social Role performance at intake significantly predicted the rate of change in parent-reported youth outcome; and Interpersonal Relations at intake significantly predicted rate of change in youth-reported outcome. Finally, changes in parent Social Role performance were associated with changes in youth symptoms over the course of treatment. Examining the associations between these variables is an important step toward identifying potential mechanisms of change in youth mental health treatment. The results of this study provide valuable information on the importance of attending to parent functioning in the assessment and treatment of youth mental health issues. Keywords: youth psychotherapy, treatment outcome, parent distress, mental health services research, usual care, Youth Outcome Questionnaire I want to express a special thank-you to my husband, Chad, and my family for all their patience and moral support through this long and rigorous process. v TABLE OF CONTENTS Introduction………………………………………………………………………………………..1 Child Psychotherapy Research……………………………………………………………3 Child/Adolescent Outcome Research in Usual Care……………………………………...4 Mechanisms of Change in Child Psychotherapy………………………………………….7 Parent Functioning and Children's Mental Health………………………………………..9 Parent Functioning and Child Psychotherapy Outcomes……………………….