Acrophobia essay
Background
Whereas some studies have shown clear evidence for an augmentation effect of D-cycloserine (DCS) on exposure therapy for anxiety disorders, other studies have shown weak effects or no effect at all. Some preclinical data suggest that the DCS augmentation effect is moderated by the success of extinction learning. Therefore, we conducted a reanalysis of existing data to examine whether the effects of DCS on clinical outcome would vary as a function of response to the exposure session (i.e., exposure success).
Methods
In a clinical trial, patients with height phobia received two sessions involving 30 minutes of virtual reality exposure therapy and were randomly assigned to a pill placebo ( n = 14) or 50 mg of DCS ( n = 15) immediately after each session.
Results
Mixed-effects regression analysis showed that the effects of DCS administration on clinical improvement was moderated by the level of fear experienced just before concluding exposure sessions. Patients receiving DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo when fear was low at the end of the exposure. In contrast, when end fear was still elevated, patients receiving DCS improved less compared with those receiving placebo.
Conclusions
D-cycloserine appears to enhance the benefits of exposure treatment when applied after a successful session, but it seems to have detrimental effects when administered after inadequate/unsuccessful exposure sessions.
Despite the overall strength of D-cycloserine (DCS) augmentation effects for extinction learning 1 2 , there is evidence of failures to find an augmentation effect in both animal 3 4 and human 5 6 7 paradigms. A number of animal studies have investigated the limits of DCS augmentation effects and indicate that augmentation effects are achieved only with animals that have demonstrated extinction at the time the DCS is administered. For example, Weber et al. (4) separated animals into
Whereas some studies have shown clear evidence for an augmentation effect of D-cycloserine (DCS) on exposure therapy for anxiety disorders, other studies have shown weak effects or no effect at all. Some preclinical data suggest that the DCS augmentation effect is moderated by the success of extinction learning. Therefore, we conducted a reanalysis of existing data to examine whether the effects of DCS on clinical outcome would vary as a function of response to the exposure session (i.e., exposure success).
Methods
In a clinical trial, patients with height phobia received two sessions involving 30 minutes of virtual reality exposure therapy and were randomly assigned to a pill placebo ( n = 14) or 50 mg of DCS ( n = 15) immediately after each session.
Results
Mixed-effects regression analysis showed that the effects of DCS administration on clinical improvement was moderated by the level of fear experienced just before concluding exposure sessions. Patients receiving DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo when fear was low at the end of the exposure. In contrast, when end fear was still elevated, patients receiving DCS improved less compared with those receiving placebo.
Conclusions
D-cycloserine appears to enhance the benefits of exposure treatment when applied after a successful session, but it seems to have detrimental effects when administered after inadequate/unsuccessful exposure sessions.
Despite the overall strength of D-cycloserine (DCS) augmentation effects for extinction learning 1 2 , there is evidence of failures to find an augmentation effect in both animal 3 4 and human 5 6 7 paradigms. A number of animal studies have investigated the limits of DCS augmentation effects and indicate that augmentation effects are achieved only with animals that have demonstrated extinction at the time the DCS is administered. For example, Weber et al. (4) separated animals into