ABSTRACT
Though popular across many audiences, engagement with a service dog has undergone limited empirical evaluation as a complementary or alternative treatment for posttraumatic stress disorder (PTSD). The present study took advantage of a service dog training intervention underway in a Department of Veterans Affairs residential PTSD treatment program to perform a within-subjects comparison of a range of phenotypic markers. The present report considers negative and positive affect, assessed throughout the day, contrasting weeks when participants were or were not accompanied by their service dog. Fifty-four veterans were studied for 2-6 weeks. Negative and positive affect were sampled five times per day using items from the Positive and Negative Affect Schedule. Participants also wore a single-patch ECG/activity recorder and slept on beds recording sleep actigraphically. Linear mixed effects regression was employed to estimate the effect of the presence of service dog on momentary affect in the context of other presumable influences. Missing data were managed using methods applicable to random and nonrandom missingness. In this sample, the presence of a service dog was associated with reduced negative and increased positive affect, with both effects diminishing over time. Only negative affect was associated with time in residential treatment, and only positive affect was associated with concurrent heart rate, activity, and the interaction of activity and prior-night actigraphic sleep efficiency. These results concur with prior reports of reduced PTSD symptomology in association with the presence of a service dog, and with the distinct neurocircuitries underlying defensive and appetitive emotion and motivation. Limitations derive from the artificial environment and brief duration of study. (PsycInfo Database Record (c) 2021 APA, all rights reserved).