The study involved 49 police officers, 25 with PTSD and 24 without PTSD. Participants completed a working-memory task both with and without their own familiar dog present.
In the PTSD group, performance was better when the dog was present. The control group showed the opposite pattern, performing slightly better without the dog. EEG measurements also showed changes in the PTSD group.
The researchers suggest that a familiar dog may reduce stress and free up cognitive resources, but the sample was small and specific, so the findings should not be generalized too broadly.