As the seasons start to change, so do our moods. Even though Tucson only has three seasons, summer, fall, and one week of winter, our mood can still change. The people who have SAD (Seasonal Affective Disorder) have to manage through the fall and winter and it can be really challenging.

According to the National Institute of Mental Health, SAD is a type of depression that sets in because of weather changes. This usually starts late fall and early winter, and then lifts once spring and summer start to arrive.  SAD has all the characteristics of major depression, so if you have the condition, you might feel depressed, fatigued, and have problems with your sleep, among other symptoms.

Some experts say that your personality type could actually make you more likely to develop SAD. The main cause of SAD is linked to shorter days and less sunlight, personality types may respond differently to these seasonal shifts. Clinical psychologists, Deborah Offner PhD told Bustle, “In part, those with personality types most susceptible to depression will be those most vulnerable to SAD, because both are mood disorders with a significant biological — as well as psychological — basis.”

NIMH also reported that people with SAD might have trouble regulating serotonin, which is a neurotransmitter involved in keeping moods stable. Also, people with SAD might be deficient in vitamin D, while producing too much of the sleep hormone melatonin. This is why you feel sluggish and tired during the different seasons.

Mother Nature Network (MMN) stated that individuals who have this order tend to be more sensitive to their environment, have a wide range of interests, and dislike routines. How individuals handle stress can also play a major role in why your mood changes during the seasons. Treatments for SAD are light therapy, anti-depression medications, and the use of melatonin.