While the holiday season is filled with parties, shopping, decorating and other festive activities, mental health experts say it often brings unwelcome guests as well: stress and depression.

While they can be difficult to manage when one is in the midst of a bout, with a few strategies one may be able to prevent both before they ruin the holiday season.

Frederic Bemak, Ed.D., a professor in counseling and development at George Mason University in Fairfax, said causes of stress and depression during the holidays can include difficult family dynamics or issues such as illness, death of family members or changes due to marriage or divorce.

"People need to have open and clear dialogues about those issues," said Bemak. "Anticipatory conversations about those issues in advance is better than arriving and then saying ‘Now what do I do?’"

Bemak advises managing one’s own issues first. Sometimes that means seeking professional help. "Gain an understanding of your issues and behaviors," he said. "If you have had a difficult relationship with a family member, you have to work on that for yourself and ask yourself ‘How do I handle those things when these issues come up?’ so you don’t get pulled back into behavior patterns that are unhealthy."

Bethesda-based psychotherapist Karen Soltes, a licensed clinical social worker who treats military veterans, said while spending time with family can be challenging, a lack of familial connection can also pose obstacles.

"During the holidays, it is hard for people who don’t have family," said Soltes. "A lot of veterans I work with are disconnected from their families and are lonely because they don’t have family to be with."

Linda Gulyn, Ph.D., a professor of psychology at Marymount University in Arlington, said high expectations can lead to anxiety and sadness as well. "Some people feel this need to spend a lot of money, which can contribute to stress, especially with parents and children," she said. "They have unrealistic expectations which can lead to profound disappointment."

In addition to dealing with possible causes, recognizing the warning signs of stress and depression can help prevent serious bouts. "One big sign that your mood is being affected is trouble with sleeping," said Gulyn. "Senses of hopelessness, guilt, regret or other kinds of negative feelings are signs, as well as overeating and alcohol or substance abuse. You’re also more likely to be more agitated with other people."

Shorter days and less sunlight are other contributors. "The holidays happen to fall in winter where we’re more likely to have our moods affected by lack of light," she said. "That is our brain’s response to reduced sunlight, which we need very much."

If one feels the warning signs of stress or depression, there are behavior modifications that can help ward off both. "Watch the alcohol consumption," said Gulyn. "Get as much activity and sunlight as possible and try to modify your expectations."

However, Gulyn says that at the top of her list is social support. "Have interactions with other people who can keep you active or give comfort, advice, fun or joy," she said. "Exercise is great, meditation is great, but nothing beats spending quality time with friends.

Soltes said, "I tell people to put themselves at the top of their Christmas list and give as generously [to] and nurture themselves as they do others in their lives. That could mean having a ‘staycation’ like staying at home in your pajamas and watching your favorite movie on Netflix."