To compare, in men with erectile dysfunction, the diagnosis obtained with the 'Leiden impotence questionnaire' (LIQ)--which differentiates between psychogenic and organic erectile dysfunction--with the clinical diagnosis based on psychophysiological diagnostic screening (PDS).Exploratory, comparative, and prospective.The LIQ-questionnaire was administered to 320 consecutive patients with erectile dysfunction who underwent PDS (i.e. visual sexual stimulation and penile vibration) in the Department of Endocrinology and Reproduction, Erasmus University Medical Centre, Rotterdam, the Netherlands. The clinical diagnosis was based on PDS and later, retrospectively, compared to the LIQ-based diagnosis (only the first six of the 11 LIQ-questions were answered by all patients).The clinical diagnosis, psychogenic or somatic, corresponded well with the LIQ-diagnosis. Following PDS an organic aetiology was assumed in 30% of the patients; compared to 33% according to the LIQ. For a psychogenic aetiology the figures were 70% and 67% respectively. Overall there was a 74% correspondence between PDS-diagnosis and the LIQ-diagnosis. Age was a significant factor: younger men (40 years) had the highest LIQ-score (compared to men aged 40-60 and60 years) and the strongest penile responses. This is indicative of a more frequent psychogenic aetiology of the erectile dysfunction in younger men.Elaborate psychophysiological diagnostic screening is not necessarily the first diagnostic choice in men with erectile dysfunction; one may start by applying the LIQ. A high LIQ-score (5-7) virtually excludes a somatic aetiology. A low LIQ-score (0-2) necessitates further psychosomatic diagnostic screening, preferably with PDS.
