Pain, negative mood, and perceived support in chronic pain patients: a daily diary study of people with reflex sympathetic dystrophy syndrome.

Chronic pain patients show substantial psychological distress, including depressed mood, anxiety, and anger. Nevertheless, the causal role of negative mood in the course of chronic pain conditions remains unclear. This study prospectively investigated the relationship between daily pain, negative mood, and social support in 109 people with reflex sympathetic dystrophy syndrome. Participants completed 28 daily diaries that included questions about pain, mood, and perceived support. Time-lagged within-subject analyses indicated that pain led to increases in depressed, anxious, and angry mood. Depressed mood, but not anxiety or anger, contributed to increases in pain. Perceived support had both main and buffering (interaction) effects on negative mood and a main effect on pain.