He studies the neural mechanisms of mindfulness using standard and real-time fMRI, and has translated research findings into programs to treat addictions.

Brewer founded MindSciences, Inc. (now known as DrJud), an app-based digital therapeutic treatment program for anxiety, overeating, and smoking.

[3] Brewer began meditating to deal with stress while a graduate student at Washington University School of Medicine.

In 2011 he and colleagues published a study reporting, "the brains of experienced meditators—those who have been meditating for at least 10 years—showed decreased activity in the areas linked to attention lapses, anxiety, attention-deficit hyperactivity disorder, schizophrenia, autism, and plaque buildup in Alzheimer disease.

The areas in question comprise the default mode network, which consists of the medial prefrontal and posterior cingulate cortices.

[8] In 2012, Brewer founded MindSciences, Inc. to create app-based digital therapeutics programs based on the mindfulness training and research he pursued in his lab at Yale University.

[9] A study on the "Craving To Quit" app found a mechanistic link between reductions in brain reactivity to smoking cues and reductions in cigarette smoking that were specific only to mindfulness training, compared to the National Cancer Institute's QuitGuide app.

[18] Brewer's clinical practice has specialized in habit change ranging from anxiety to unhealthy eating to addiction.

He began his career at the Veteran's Administration Hospital in West Haven, CT where he was also an assistant professor in the department of psychiatry at the Yale School of Medicine.

[19] In 2023, he co-founded Mindshift Recovery, a non-profit organization based on his research, dedicated to helping individuals with addiction that combines app-based training with peer mentorship.

[24] Markham Heid of Time quoted Brewer's explanation of his research findings in 2014: "Basically, meditation helps your brain get out of its own way...

"[27] On 60 Minutes, Anderson Cooper featured his own experiences at a mindfulness meditation retreat[28] and visited Brewer "to learn more about the cutting-edge brain imaging research he is conducting to confirm that mindfulness can be an effective treatment for addictions to everything from food to tobacco to opioids—even to electronic devices like cell phones.

[30] Fran Smith wrote in 2017, "In a head-to-head comparison, Brewer showed that mindfulness training was twice as effective as the gold-standard behavioral antismoking program.

Brewer and others have shown that meditation quiets the posterior cingulate cortex, the neural space involved in the kind of rumination that can lead to a loop of obsession.When Amanda Lang of Bloomberg TV Canada asked Brewer why employers are interested in mindfulness, he said if employees can develop the wisdom to understand how they and their co-workers' minds work, it could help all work together in a much more seamless manner.

When asked about the possible downsides, he did not offer any negatives associated with such a change, but he did mention the importance of working with a teacher or facilitator.

"[34] To achieve self-compassion, Brewer recommended using "any practice that helps us stay in the moment and notice what it feels like to get caught up.