Although the Hofmann et al. study did not demonstrate significant between-group differences at follow-up, it did confirm an enhanced rate of improvement. In contrast, the study suggests that repeated dosing of d-cycloserine over days offers little benefit over single doses, and that future studies, which seem to be merited, should use longer intervals—perhaps up to 1 week—between treatments. On theoretical grounds, it might also be preferable to administer d-cycloserine or other NMDAR agonists after, rather than before, CBT sessions and to administer it only after sessions in which significant improvement has been observed. Finally, future research should probably involve fewer subjects studied more intensively, so that mechanisms of both successes and failures can more easily be translated into improved treatment approaches.