Therapeutic incubation—a ritual sleep practice in ancient Greek healing sanctuaries such as the Asclepieia—was used to induce apocalyptic dreams for healing. Although originally mystical, the concept parallels modern holistic and personalized medicine. This practice played a key role in transitioning medicine from empirical traditions toward scientific approaches, sowing seeds for modern therapy. The study examines therapeutic incubation as a holistic patient approach and a placebo effect, and explores its connections to contemporary therapeutic procedures.
Higher cortisol levels, measured in saliva, are linked to increased dream recall and more positive dream affect. In a sample of 15 men and 15 women, those with higher evening or morning cortisol tended to recall more dreams. A statistically significant association emerged for morning cortisol levels above 19.1 nmol/L, where the odds of recalling a dream with positive affect were over four times higher. No connection was found between menstrual cycle phase and dream recall or affect. Cortisol may be an important modulator of dreaming, warranting further research.