The investigators will measure and compare the immediate effect of the presence of the dog, on days with low stress and high stress, using non-invasive measures of the physiological response, diary notes, and data on activity and sleep pattern The latter will also be collected for the service dogs. The investigators will apply a cross-sectional design. The participants will be divided into two groups based on whether they own a certified service dog (treatment group) or are on a waitlist for a service dog (control group).~The experimental period will consist of a 14-day period. In the preceding week the participants receive a visit, where they will be given instructions to fill in a diary, how to collect and store saliva samples, and use equipment for data collection. In the diary they record their daily activities and any situation perceived to be stressful during the experimental period. In the experimental period, the participants will wear an accelerometer. Every second day, the particpants will wear equipment measuring their heart rate.
The study aims to investigate the effects of a service dog on military veterans with post traumatic stress syndrome (PTSD). The investigators will use non-invasive measures of the physiological responses, data obtained via dairy keeping, accelerometer data estimating activity and sleep patterns, and baseline information including psychological measures validated for this specific population.