Approximately 1 in 4 adults suffers from some form of mental illness in a given year, and almost $150 billion is spent annually on the treatment of mental disorders;however, only half of individuals seeking treatment for psychopathology actually experience clinically significant improvement. The overall objective of the proposed research is to develop and test an integrated theoretical model explaining how key risk factors interact to contribute to the developmental courses of internalizing (depression and anxiety) and externalizing (alcohol use) disorders, by integrating key components of diathesis-stress, internalizing, and externalizing models of psychopathology and a vulnerability-stress-adaptation model of relationship dysfunction. My central hypothesis is that genetic vulnerabilities for mental illness contribute to greater environmental stress and poorer relationship functioning, which in turn contribute to the course of psychopathology. There are 5 specific aims to the proposed research to be tested across 2 independent studies. Study #1: Aims 1 -2 will be examined in a sample of 275 community couples assessed 6 times over 7 years. The 1st aim is to explain the longitudinal associations between global relationship discord and psychopathology symptoms over the first 7 years of marriage, to determine the extent to which intimate relationships contribute to the developmental course of psychopathology. The 2nd aim is to develop an integrated conceptual framework using Kraemer et al.'s criteria to explain how relationship functioning interacts with genetic vulnerabilities and environmental stress to contribute to the development of psychopathology symptoms. The 3rd aim is to identify the specific relationship processes (e.g., support, conflict) contributing to the development of internalizing and externalizing symptoms within the framework developed in Aim 2. Study #2: Aims 4 and 5 will be examined in a clinical sample (100 outpatients) assessed once. The 4th aim is to develop a framework using Kraemer et al.'s criteria that explains how global relationship functioning interacts with genes and stress to contribute to current diagnoses of psychopathology. The 5th aim is to identify the specific relational processes associated with concurrent internalizing and externalizing disorders for treatment-seeking individuals. Self-report questionnaires and objective semi-structured interviews will be implemented. The proposed research is the first step toward my long-term goal to develop/enhance prevention and treatment programs targeting depression, anxiety, and alcohol use disorders and has particular relevance to public health given its potential to reduce the burden of mental illness in our society.