Positive events were differentiated according to their degree of categories of personal control and causation and were related to positive affect (PA), and negative affect (NA), and to the degree of the PA–NA relationship. Arthritis patients and healthy controls were interviewed for 12–20 weeks on life events and PA and NA. Baseline measures on extraversion and neuroticism also were assessed as possible confounds in multilevel modeling tests of events and affect relationships. Results showed that positive controllable and internally caused events (PCI) and positive uncontrollable and externally caused events (PUE) were related to increased PA. PUE were related to increased NA, while PCI events were related to reduced NA. As predicted, there was a significant interaction of PCI events on the PA–NA relationship, relating to a reduced inverse correlation between the affects. The data suggest that causation of positive events is a significant factor in emotional complexity. Implications of the results are discussed.