In humans, Seasonal Affective Disorder is a type of depression that correlates to the change in seasons, says Kandace L. Nollie, LMHC, a licensed mental health counselor and program director at Chrysalis Health in Brandon, Florida. It most often occurs in winter, but rare cases can happen in the spring or summer months. While the exact cause can vary and is often unknown, it can sometimes be caused by changes in sunlight, sleep patterns and shifting levels of melatonin—a chemical known to affect sleep (which can be caused by those changes in sunlight, in and of itself). Treatments for SAD in humans may include using special lights to counter decreases in sunlight, medication and/or cognitive behavioral therapy (a common type of talk therapy), according to Cleveland Clinic.,Approximately half a million Americans suffer from seasonal depression, also known as Seasonal Affective Disorder (SAD). You may be familiar with this form of depression that has a seasonal pattern, and wouldn’t wish it upon anyone—let alone your best fur friend! But wait—is that something you need to worry about as a pet parent? Can dogs and cats get seasonal depression? If your pet just doesn’t seem to be themselves come winter, it turns out that, yes, it could be because of Seasonal Affective Disorder. In fact, it’s actually pretty common: About one-third of pet parents report seeing a shift in their dog’s mental state and energy during the winter, according to veterinarian Dr. Albert Ahn, DVM, Veterinary Advisor for Myos Pet, a senior pet healthcare company in Cedar Knolls, New Jersey. “Considering there are about 90 million dogs owned in the U.S., that equates to around 30 million in total, which would suggest that it is quite common,” Dr. Ahn says. Don’t panic though! We found out exactly what you need to know about seasonal depression in pets—including the signs, when to call your vet and the not-so-scary treatment options.