Smartphones can help dieters lose weight. They can track our activity levels. They can also help cheer you up and calm you down.

Researchers at Northwestern University have created a series of smartphone apps designed to make you feel good. People who used them over an eight-week study saw the severity of their depression and anxiety symptoms drop by about 50%.

Designed to Be Simple and Fast

The 13 apps, called IntelliCare, work together to target common sources and symptoms of depression and anxiety — like sleep problems, loneliness and social isolation, lack of activity and obsessive thinking. The apps aren't just for people who are depressed or anxious. They can help you sleep better, meditate, challenge negative thinking and be kinder to yourself. If you have been struggling with certain New Year's resolutions, they may offer useful support.

“We designed these apps so they fit easily into people's lives and could be used as simply as apps to find a restaurant or directions,” study author, David Mohr, professor of preventive medicine and director of the Center for Behavioral Intervention Technologies at Northwestern University Feinberg School of Medicine, said in a statement. People reported using the apps for about one minute a session on average and between three and four times daily.

The drop in the severity of depression and anxiety in the preliminary study of 96 people was comparable to that expected from standard therapies such as psychotherapy or antidepressant medications.

They can help you meditate, challenge negative thinking, and be kinder to yourself.

Because the study had no control arm — no one was excluded from using the apps — it can't show definitively that the apps were behind the improvement. It's possible that the people might have gotten better without them. The study does suggest that the apps are effective, and a larger study with 300 people that does have a control group is already underway.

Among the apps that are available:

  • Worry Knot — Teaches you how to spend less time worrying. From finding solutions to knotty problems to breaking the chains of tangled thinking to simply distracting yourself, Worry Knot offers a variety of different approaches.

  • Boost Me — When feeling down or stressed, Boost Me can remind you of activities that have lifted your mood in the past or suggests new ones to try. Its log lets you keep track of what works best and what doesn't work at all.

  • Thought Challenger — Negative thoughts can have a life of their own. But do they stand up under scrutiny? Thought Challenger helps you test them out and can lead you to a more balanced perspective on life and on yourself.

  • Move Me — 10 to 15 minute bursts of activity improve mood and well-being. They're good for the body, too. All it takes is a little motivation. From motivational tips to offering the latest exercise videos to helping you set up and keep on an exercise schedule, Move Me offers several different ways to get out of the chair or couch and start moving.

    • The full suite of apps can be downloaded for free. Each is designed by clinicians; and though they have not yet been validated, all are based on validated techniques used by therapists.

    The idea is to help the millions of people who want support but can't get to a therapist's office, Mohr said.

    The study appears in the Journal of Medical Internet Research.