Improving exposure therapy for child anxiety with D-Cycloserine and one-session treatment

Exposure therapy is an important component of treatments for childhood anxiety, however, not every child responds to this technique. This thesis examined strategies to improve exposure therapy for anxious children. The first empirical study evaluated the effects of a single, prolonged exposure session (One-Session Treatment: OST) on harm beliefs in children experiencing dog phobia. The results indicated that harm beliefs predicted distress towards a dog before exposure and avoidance of the dog after exposure. This finding was consistent with theory in adults which posits harm beliefs maintain a phobic response. This study also demonstrated the efficacy of OST for reducing harm beliefs in children. 

The thesis then reviewed literature which examined the potential for D-Cycloserine (DCS) to pharmacologically augment exposure therapy for children. This review described research from both rats and adult humans, which indicated DCS prevents relapse after exposure by consolidating fear extinction learning into memory. As relapse often occurs when the new learning does not extend beyond the therapy setting, this thesis particularly examined whether DCS enhanced generalization of fear extinction. The second study attempted to investigate whether DCS enhanced generalization of extinction across contexts in rats. However, this study could not first replicate DCS’s retention of extinction when context was controlled, so its effects on generalization could not be investigated. 

The previous null DCS effect may have been due to poor within-session extinction, so for the next study which examined DCS augmentation in children, good fear extinction was ensured. In a randomized controlled trial, children experiencing dog or spider phobias ingested either 50mg of DCS or a placebo prior to OST for their phobia. This study found that children who ingested DCS demonstrated less avoidance and fear when a different exemplar of their feared stimulus was presented in a novel context one week after treatment. This result provided evidence that DCS can enhance generalization of fear extinction learning as early as middle childhood. Having demonstrated DCS can augment exposure therapy in children, the final empirical study investigated whether parents would allow their children to take DCS if recommended by a psychologist. A community sample of parents reported mixed attitudes towards the use of DCS for their children. Many said they would consider using DCS, however, they also reported significant concerns regarding its use, particularly with regard to the potential for side-effects.

Based on the studies in this thesis and more recent research described in a second review paper, the thesis concluded that DCS shows promise for augmenting the treatment of child anxiety. However, further research is needed to determine whether it has benefits greater than current therapies such as OST. It argues there is a continued need for awareness regarding parental concerns towards DCS. It also provides further evidence for the efficacy of OST for treating childhood phobias.