1. ¹Department of Neuroendocrinology, University of Lübeck, Germany
2. ²Department of Internal Medicine, University of Lübeck, Germany

Correspondence: Dr J Born, Institut für Neuroendokrinologie, Universität zu Lübeck, Ratzeburger Allee 160, Haus 23a, D-23538 Lübeck, Germany. Tel: +49 451 500 3641; Fax +49 451 500 3640; E-mail: born@kfg.mu-luebeck.de

Received 26 September 2002; Revised 8 January 2003; Accepted 5 March 2003; Published online 14 May 2003.

Abstract

Previous studies indicated an enhanced capability of divergent creative thinking in young women during the ovulatory phase, which expressed itself also by an increased dimensional complexity of ongoing electroencephalographic (EEG) activity. Considering the enhanced plasma levels of estrogen and testosterone characterizing the ovulatory phase, we tested whether short-term administration of estrogen or testosterone in postmenopausal women with constantly low levels of gonadal steroids induces similar changes in divergent thinking. In two placebo-controlled cross-over studies, healthy postmenopausal women (n=12, in each study, mean age 58 years, range 47–65 years) were treated transdermally over 3 days with estrogen and testosterone, respectively, at doses inducing plasma hormone concentrations comparable with those observed in young women around ovulation. Capabilities of divergent thought and convergent analytical thought, performance on motor perseveration, and verbal memory were examined. EEG activity was recorded while subjects performed on tasks of thinking and during mental relaxation. Estrogen impaired divergent thinking (p<0.01) and enhanced convergent thinking, motor perseveration, and memory for the initial word list (p<0.05 for all tests). In parallel, EEG dimensional complexity was reduced (p<0.05). Overall, these changes indicate an estrogen-induced shift from a 'divergent' towards a more 'convergent' mode of processing. However, overall less consistent, effects of testosterone were opposite to those of estrogen. It increased performance on some of the divergent thinking tasks (p<0.05), and tended to increase EEG dimensional complexity during divergent thinking. Data indicate a differential sensitivity of modes of thinking to short-term treatment with estrogen and testosterone in postmenopausal women.