Today is Vesak, the celebration of the life of the Buddha, which inspires me to write about mindfulness as a strategy for maintaining wellness. Really, anyone can practice mindfulness, but it has become a common practice to incorporate the Buddhist practice in mental health treatment.
I first learned about what is called "core mindfulness" through a hospital in Chicago that was teaching Dialectical Behavioral Therapy (DBT) to patients. To keep this from getting too technical, I'll just give you my take on it. It basically means pay careful attention to what you're doing. For example, if you're doing a simple task like taking a shower, really notice the experience: the water temperature on your skin, the feeling of wetness, the soap suds in your hair and on your body, the look and feel of the shower stall around you, etc. You can try it for short periods of time and then try to keep your attention focused for extended periods.
I know that DBT / core mindfulness was really challenging for me when I was hearing voices all the time. It was hard for me to even pay attention to something engaging like TV, let alone a mundane task. The voices had my attention. Mania can also make it really hard to concentrate because you can't really rest, so you're not fully awake. With depression, negative thoughts are at the forefront of your mind. In general, when your mind is troubled, you tend to be distracted. Practicing mindfulness really helps.
If you want to learn more about this incredibly helpful practice passed down to us through Buddhism, here's a good article: http://www.goodtherapy.org/blog/dialectical-behavior-therapy-dbt-core-mindfulness/.
Happy Buddha Day! Om!