The differential functions of imagery and verbal thought in insomnia.

Individuals with insomnia were exposed to a stressor (speech threat) prior to getting into bed and were instructed to think about the speech and its implications in either images (Image group, n = 14) or verbal thought (Verbal group, n = 17). Participants completed questionnaires about speech anxiety, arousal, and sense of resolution. Measures were taken of subjective (sleep diary estimates) and objective (actigraphy) sleep-onset latency. In the short term, the Image group reported more distress and arousal relative to those in the Verbal group. In the longer term, the Image group estimated that they fell asleep more quickly and, the following morning, reported less anxiety and more comfort about giving the speech compared with the Verbal group.