Parenting stress and salivary cortisol in parents of children with autism spectrum disorder: Longitudinal variations in the context of a service dog’s presence in the family

•Parents of children with ASD perceived high levels of parenting stress at baseline.•They showed low morning cortisol activity at baseline.•Perception of stress predicted morning cortisol activity at baseline.•Hypocorticolism related to chronic stress observed in parents of children with ASD.•Parenting stress, wakening and morning cortisol decreased with the dog’s presence. A significant portion of parents of children with autism spectrum disorder report high levels of stress related to parenting responsibilities, which have been linked to abnormal cortisol patterns. This study seeks to better understand the parents’ adaptation to caregiving demands and use of a service dog, by taking into account longitudinal variations in salivary cortisol and perception of parental stress. Salivary cortisol was collected one day per week for 15 weeks by 98 primary caregivers of children with ASD. Overall, parents perceived high levels of stress at baseline. Mean morning cortisol increase was below expected levels for healthy adults, and perception of stress predicted morning cortisol activity. Hypocorticolism related to chronic stress may be present in parents of children with ASD. Longitudinal analysis revealed that the presence of a service dog in the family had an effect on parenting stress, wakening and morning cortisol levels.