Pilot study of a water load test as a measure of gastric interoception in anorexia nervosa.

Purpose: Research and clinical experience suggest that individuals with anorexia nervosa (AN) have deficits in gastric interoception, which has been hypothesized to maintain restrictive eating. Behavioral water load tasks (WLTs) have the capability to noninvasively assess gastric interoception; however, to date, no studies have examined WLTs in AN. Thus, the present proof-of-concept pilot study explored the preliminary validity of a WLT in individuals with AN.

Methods: Participants were n = 10 individuals with AN and n = 10 matched-control women (CW). Participants completed self-report questionnaires before and after a WLT, in which participants were asked to drink water until "completely full".

Results: Participants with AN drank significantly less water than CW (AN = 240(109.14) milliliters (ml), CW = 398.00(149.21) ml, p = 0.02, Cohen's d = 1.21), but reported greater increases in negative affect pre- to-post-WLT (p = 0.04, partial eta = 0.21). Correlations between WLT performance and interoceptive sensibility in AN and CW participants supported the convergent validity of the WLT.

Conclusion: Preliminary results support the potential utility of the WLT as a behavioral measure of gastric interoception in patients with AN. Future research should examine how response to the WLT changes over the course of intervention and how results are related to treatment outcome.

Level Of Evidence: Level IV: Evidence obtained from multiple time series analysis such as case studies. (NB: Dramatic results in uncontrolled trials might also be regarded as this type of evidence).