We have to fight our brain's wandering thoughts that leave us feeling depressed and unfulfilled. YouTube/CallMeKat Do you ever feel mad or sad or anxious and wish you could just snap out of it?

Well, you might just be able to.

Amit Sood, an MD and professor of medicine at the Mayo Clinic College of Medicine, has spent two decades meeting with hundreds of scientists, reading thousands of research papers and books, and studying tens of thousands of patients and students to figure out how we can stop our minds from being consumed by stressful thoughts.

In his book "The Mayo Clinic Handbook for Happiness," Sood concludes that the human brain is continually switching between two modes: default mode, which is when our minds are distracted or begin wandering, and focused mode, in which our minds are highly focused on something interesting.

The research that Sood cites suggests that our brains are in default mode, letting our thoughts wander (you know, when you've finished reading a paragraph without knowing what you read, or pulled into your garage without knowing how you got home safely) for at least half of our waking hours. When we enter this mode, we're more likely to descend into thoughts that can bring us down, like: "I wonder what Ellen really thinks about me? She hasn't texted me in a while. She's probably mad I didn't join her book club. I promised myself I'd start reading more--"

While a wandering mind is necessary every once in a while to help you make connections, be creative, and brainstorm, many people spend too much time there, Sood says, and indulge in negative, rather than productive, thinking.

Spending too much time in this mode means you might obsess over unlikely what-if scenarios or spend too much time thinking about what people "really" think about you, which can cause stress, depression, anxiety, and a lack of happiness, he says.

To avoid spending too much time in default mode, Sood suggests focusing your attention on one thing at a time.



Think of a time when you were so lost in a fascinating task that you forgot your everyday concerns. Sood says that's your brain's focused mode — when you "fully attend to the world, appreciating its novelty and meaning."

You tend to feel happier in this mode, he says, because you're taking in something that interests you and you have fewer distractions.

Most of us tend to go into this mode when we do things like read a good book, spend time with a loved one, meditate, or eat a great meal.

Sood says we can encourage our minds to enter this focused approach by looking for novel and meaningful things in the external world and by intentionally choosing what to think about. This means taking control rather than letting thoughts happen to you.

For example, when thinking about your child's coming birthday, a focused mind might think, "Is she old enough for a cellphone, or should I stick with a tablet or coloring book?" Still, it's easy to slip into default mode and start thinking: "Should we invite Anna to the party? Her mom didn't smile at me yesterday so I don't think she likes me." And these can quickly spiral into worried thoughts about finances, relationships, work, and family, Sood says.

Do your well-being a favor and fight these thoughts. "I believe we all need to dial down the dialogue in our heads and make our thoughts more positive and productive," Sood writes.