Evaluating the effects of a brief motivational interviewing protocol on excessive acquisition

Individuals with hoarding disorder, especially those with problems around acquiring, typically demonstrate a lack of motivation and awareness of their problematic behaviours. Since acquiring behaviours are important targets in interventions for hoarding, effective strategies for increasing motivation in this population are required to enhance the acceptability and efficacy of these interventions.

The aim of the current study was to evaluate the ability of a brief online motivational intervention to reduce acquiring in a community sample of high acquirers (N = 159). Participants were randomly assigned to either a motivational interviewing protocol (n = 73) or progressive muscle relaxation control condition (n = 86). Readiness to change and motivation to acquire was measured via self-report, and acquiring behaviour was measured using a modified version of the Preston Acquisition Decision Making Task (to increase ecological validity).

In both conditions, participants' readiness and motivation to change increased over time. Contrary to hypotheses, the magnitude of this improvement did not significantly differ between conditions. Furthermore, conditions did not perform differently on the behavioural measure of acquiring.

Insufficient dose of the intervention may have precluded any differences being observed between conditions.

Results underscore the need to better address the problem of lowered motivation in this population.