However, a review study published today in PLOS One finds little evidence for any overall health “pet effect.” Pet owners reported poorer physical health than non-pet owners, a trend the study authors attribute partly to the higher frequency of cigarette smoking by pet owners. That said, pet owners who spent more time with their animals reported higher psychological well-being than those who spent less. Keeping in mind that the results were correlation rather than causation, the study authors concluded that pet ownership doesn’t automatically improve people’s physical or mental health. “Pet ownership is a multidimensional construct that includes characteristics of the owner, the animal, and their relationship.”