Correlation of nocturnal penile tumescence and daytime affect intensity in depressed men

Although depressed patients have been shown to have diminished nocturnal penile tumescence (NPT), there remains considerable variability of NPT in depression. We hypothesized that affective experience during the day accounts for some of this variability. Forty-five depressed men had assessments of affect intensity and affect balance, NPT, and daytime sexual function, both before and after treatment with Beck's cognitive behavior therapy (CBT). Forty-three normal control subjects were studied for comparison. Daytime affect intensity in depressed men, but not in control subjects, correlated significantly and positively with measures of NPT duration and rigidity both before and after treatment, regardless of the adequacy of daytime sexual function. When the effect of daytime affect on REM activity was controlled, the observed correlations became nonsignificant at pretreatment, but remained significant at posttreatment. Neuropharmacologically mediated changes in arousal responsivity associated with depression may underlie the observed relation between daytime affect intensity, rapid eye movement activity, and NPT.