Abstract
Objective: Previous theory suggested that nightmares may partly result from a concretization process in which vague dysphoric inner states are made more tangible symbolic imagery. However, research has yet to specifically examine this possibility. The aim of the current study was to examine if a concretizing style, a hypothetical propensity to experience concretization in sleep and waking states, and its proposed manifestations (hallucinatory activity, projection, vivid fantasy, and acting out of inner states) related to nightmares.

Methods: Using a cross-sectional design, a sample of 215 adults drawn from a non-representative sample completed measures of nightmare frequency, hallucinatory activity, projection, vivid fantasy, acting out, neuroticism, sleep length, and a newly devised measure of a concretizing style.

Results: After controlling for neuroticism, sleep length, and sociodemographic variables, concretizing style was independently related to hallucinations, projection, vivid fantasy, and acting out of inner states. Hallucinatory experiences, vivid fantasy, and acting out of inner states, but not projection, independently related to nightmares. The concretizing style measure indirectly related to nightmares through hallucinations, vivid fantasy, and acting out inner states, but not projection.

Conclusion: The results were consistent with theoretical predictions that a concretizing style and its manifestations may be involved in nightmare production. The data suggests that structures involved in hallucinatory experiences, vivid fantasy, and acting out of inner states may play a role in a concretizing style resulting in nightmares. Patients reporting hallucinatory activity, vivid fantasy, and behavioral issues might need to be evaluated for nightmares as well, and vice versa. The results and future directions for research were discussed.

Key words: Nightmares; Concretization; Hallucinations; Fantasy; Acting Out; Projection