Mindfulness is now a billion-dollar industry,

with as many as 1 in 5 Fortune 500 companies

implementing some kind of workplace mindfulness programs.

It has been rebranded from "hippy dippy nonsense"

to portrayals such as "brain training," said to "sell it better."

These reductionist, commodified forms have been derided as "McMindfulness,"

but who cares what they call it if it works. But does it?

Research into mindfulness has been complicated by the fact

that the term can mean anything from informal practices,

such as conscious awareness while eating,

to structured meditation programs involving designated specific times

to sit in a specific posture attending to your breathing, for example.

This has made an understanding of the efficacy hard to capture.

It can't hurt, though, right?

Well, there have been more than 20 observational studies or case reports

documenting instances of adverse effects,

such as meditation-induced psychosis, mania, anxiety, panic.

In one prospective study of an intensive meditation retreat,

60% reported at least one adverse effect,

including one individual who was hospitalized for a psychotic break.

Even outside of an immersive retreat environment,

as many as 12% of meditators recall serious negative side effects

within 10 days of initiating the practice.

It's considered plausible that adverse effects occur

at rates approximating that of psychotherapy,

with about 1 in 20 reporting lasting negative effects

of psychological treatment.

With about 18 million Americans practicing meditation and

as many as a million new meditators a year, even a 5% adverse event rate

could mean hundreds of thousands of negative side effects a year.

As with any medical intervention, though,

it's all about risks versus benefits.

Unfortunately, many of the benefits appear to have been overstated.

This commentary in

the Journal of the American Psychological Association

notes that even the books on mindfulness written by scientists

are bursting with magical promises of peace, happiness and well-being.

Contrary to the popular perception, the evidence for even

the most well-founded benefits are not entirely conclusive.

This is not an issue unique to meditation, of course.

There is a "replication crisis"

across the entire field of experimental psychology,

where many of the landmark findings in the social sciences

published in even the most prestigious journals

don't appear to be reproducible.

Drug companies aren't the only ones to suppress the publication of studies

that don't come out the way they wanted.

The majority of mindfulness-based trials apparently never see the light of day,

raising the specter of a similar publication bias.

Presumably if the studies showed promising results,

they would have been released rather than shelved.

And even many of the ones that do make it into the scientific record

are underwhelming.

The federal Agency for Healthcare Research and Quality

published a systematic review of the available data

and concluded that mindfulness meditation

worked best for improving anxiety, depression, and pain,

but even then, the quality of evidence was only moderate.

What about weight loss?

Mindfulness-based modalities can help with stress management,

self-control and decreased impulsive eating,

as well as binge eating and emotional eating,

all of which might facilitate weight management.

However, a systematic review of the evidence

published about 5 years ago

failed to find evidence of significant or consistent weight loss.

Part of the problem is compliance.

Like any other diet or lifestyle intervention,

mindfulness only works if you do it.

For example, randomize women to attend four 2-hour workshops

that teach mindfulness techniques such as cognitive defusion,

and after six months, they lost no more weight on average

than the control group.

However, if you exclude those who reported 'never' applying

the workshop principles at all and just look at those

who at least used them some of the time,

their weight loss did beat out the control group by about five pounds.

Other studies have shown a lack of weight gain rather than loss.

For example, this study found that obese subjects in the control group

continued to gain weight at about a pound a month, whereas the weight

of those in the mindfulness intervention group remained stable.

Put all the studies together and the latest and largest review published

did find mindfulness-based interventions can lead

to weight loss compared to doing nothing,

an average of about 7 pounds over around 4 months.

Pitted head-to-head,

they didn't beat out other lifestyle change interventions,

but the nice thing about stress management and mindfulness

is that they can be practiced on top of whatever else you're doing.