Could Greater Time Spent Displaying Waking Inactivity in the Home Environment Be a Marker for a Depression-Like State in the Domestic Dog?

• Published in: Animals (Basel) Vol. 9; no. 7; p. 420
• Main Authors: Harvey, Naomi D, Moesta, Alexandra, Kappel, Sarah, Wongsaengchan, Chanakarn, Harris, Hannah, Craigon, Peter J, Fureix, Carole
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.07.2019; MDPI
• Subjects: affective-state; anhedonia; Animal cognition; Animal shelters; Boredom; Correlation analysis; depression-like state; Dogs; Domestic animals; Etiology; Food consumption; Hedonic response; Home environment; Hypotheses; kennelled dog; Laboratories; Mental depression; Mental disorders; Public domain; Qualitative analysis; qualitative behaviour assessment; Shelters; Studies; Sucrose; waking inactivity; kennelled dog; depression-like state; waking inactivity; affective-state; qualitative behaviour assessment; anhedonia
• ISSN: 2076-2615; 2076-2615
• DOI: 10.3390/ani9070420

Dogs exposed to aversive events can become inactive and unresponsive and are commonly referred to as being "depressed", but this association remains to be tested. We investigated whether shelter dogs spending greater time inactive "awake but motionless" (ABM) in their home-pen show anhedonia (the core reduction of pleasure reported in depression), as tested by reduced interest in, and consumption of, palatable food (Kong test). We also explored whether dogs being qualitatively perceived by experts as disinterested in the food would spend greater time ABM (experts blind to actual inactivity levels). Following sample size estimations and qualitative behaviour analysis ( = 14 pilot dogs), forty-three dogs (6 shelters, 22F:21M) were included in the main study. Dogs relinquished by their owners spent more time ABM than strays or legal cases (F = 8.09, = 0.032). One significant positive association was found between the Kong measure for average length of Kong bout and ABM, when length of stay in the shelter was accounted for as a confounder (F = 3.66, = 0.035). Time spent ABM also correlated with scores for "depressed" and "bored" in the qualitative results, indirectly suggesting that experts associate greater waking inactivity with negative emotional states. The hypothesis that ABM reflects a depression-like syndrome is not supported; we discuss how results might tentatively support a "boredom-like" state and further research directions.