Reliability and validity of a new sexual function questionnaire (Nagoya Sexual Function Questionnaire) for schizophrenic patients taking antipsychotics.

OBJECTIVE

This study aims to validate a new user-friendly sexual function questionnaire (Nagoya Sexual Function Questionnaire [NSFQ]) for schizophrenic patients taking antipsychotics.

METHODS

Schizophrenic outpatients (men = 30, women = 30) were asked to fill out the NSFQ at initial entry into the research program (Time₁) and again 1 to 2 weeks later (Time₂). To assess the convergent validity of the NSFQ, at Time₁, subjects were asked to fill out the Japanese version of the Udvalg for Kliniske Undersogekser Side Effect Rating Scale (UKU). To assess the discriminant validity of the NSFQ, at Time₁, subjects were also asked to fill out the Japanese version of Epworth Sleepiness Scale.

RESULTS

Results from Cronbach's alpha analysis indicated that the NSFQ demonstrated excellent internal consistency and scale reliability. The NSFQ also demonstrated strong test-retest reliability. The NSFQ total score was highly correlated with the UKU total score. The NSFQ was shown to have good convergent validity with the UKU. The NSFQ total score was not correlated with the Japanese version of Epworth Sleepiness Scale total score.

CONCLUSIONS

This study revealed the internal consistency, test-retest reliability, and convergent and discriminant validities of the NSFQ.