A growing body of literature indicates that positive affect may have a unique adaptive role in the process of adjustment to chronic stress, independent of the effects of negative affects like depression. The overarching goal of this research is to provide evidence and direction for the development of interventions for people with HIV that include a focus on positive affect. To this end, this study will document the occurrence, predictors, and consequences of positive affect during the 18 months post-notification of HIV+ serostatus. This is a longitudinal cohort study in which 250 participants recruited from 4 San Francisco Bay area sites will be interviewed 7 times over the course of 18 months after notification of HIV+ serostatus. Data will consist of quantitative questionnaires, qualitative interviews (audio taped), and CD4 and viral load measures. The specific aims of the study are to: 1) Document the co-occurrence of positive and negative affect in response to notification of HIV+ serostatus (and the cascade of associated stressors) over the course of 18 months in a sample of 250 men and women; 2) Explore the potential adaptational significance of positive affect by examining its unique concurrent and prospective associations with adherence, HIV risk behaviors, healthcare utilization, health behaviors, role functioning, quality of life, and symptoms of clinical depression; and 3) Identify coping processes (e.g., problem focused coping, positive reappraisal, meaningful events) and coping resources (e.g., social support, self esteem, optimism) that are uniquely associated with increases in positive affect over time. In addition, we have two secondary aims: 1) To explore the association of positive affect with progression of HIV as evidenced by CD4, viral load, and symptoms; and 2) To explore the association of positive affect with cost of HIV treatment based on healthcare utilization and medication costs.