This raises the question of bias in supervised studies. Partnership as well as close professional supervision create high functional social support (FSS) [49]. It has been shown that FSS can have a positive effect on the proportion of days abstinent [50] and can predict treatment retention and reduction of alcohol intake [51]. A recent study has shown that FSS is associated with a higher cumulative abstinence [49]. It is probable that the positive influence of strong support had an important impact on compliance and contributed to reducing the use of alcohol. This might explain why supervised treatments had a superior success rate compared to unsupervised treatments. Nevertheless, when bias was eliminated by looking only at supervised studies in which both control and disulfiram arms were supervised, eight out of ten showed a superior performance of disulfiram compared to controls. There seemed to be no bias of social support on the superior performance of disulfiram compared to controls amongst supervised studies in which both arms were supervised.
