ABSTRACT
Sociopsychological factors play a critical role in the pathogenesis of erectile dysfunction (ED). An optimal therapeutic regimen is supposed to bring sociopsychological benefits to both the patients and their partners. Psychological and Interpersonal Relationship Scales (PAIRS) is an effective measure for evaluating the impact of ED on the psychological aspects and interpersonal relationship of the patients and their partners, as well as for predicting the satisfaction of ED patients with the treatment. PAIRS scores on the effects of phosphodiesterase type 5 inhibitors on ED show a significant decrease in sexual activity-related time concerns of the patients treated with tadalafil, as compared with those medicated with sildenafil or vardenafil. This also underlies the preference of the patients and their partners for tadalafil in clinical practice. The drug attribute associated with the decreased time concerns is the long and outstanding efficacy of tadalafil for up to 36 hours.