The Problem

The WHO estimates that depression and anxiety together account for 75,000,000 DALYs annually, making up ~5% of total DALYs. In “Measuring the Impact of Mental Illness on Quality of Life”, I argue that there is good reason to think that the system used to generate these estimates severely underestimates the impact of mental illness, and thus the true damage may be much higher. To try to get an estimate on the harms of mental health and the benefits of alieviating mental health problems, I did a preliminary cost-effectiveness analysis of Mindfulness Based Stress Reduction (MBSR).

The Intervention

MBSR is an eight week class that uses a combination of mindfulness, body awareness, and yoga to improve quality of life and perhaps physical health for a variety of conditions.

MBSR was created by Jon Kabat-Zinn at the University of Massachusetts in the 1970s, but has spread widely since then. The exact extent of this spread is hard to measure because no official registration is required to teach mindfulness and many classes and books claim to be mindfulness inspired. For the purpose of this evaluation I looked only at things that were officially MBSR or adhered very closely to the description.

Cost of MBSR

Herman, et al. (2017) estimated the marginal cost of an MBSR class participant at $150. The first three hits on google (run in an incognito browser but suspiciously near the location from which I ran the search) for MBSR listed a cost of $395-$595, $275-$425, and $350. The difference between the top of the range and the marginal cost indicates that the high end of that range probably covers all of the costs involved with MBSR (space rental and instructor time for eight weeks of classes plus one eight hour retreat) and then some, so I will use $600 as the ceiling on costs and $150 as the floor.

MBSR has an unusually high time ongoing cost (one hour per day). To model this, I included a range of DALYs as a cost, ranging from 0 (indicating no cost) to 1/24 (as if the participant were dead for that hour). It is unclear how the one hour duration was chosen and I could not find any studies on the comparative impact of different lengths of meditation; it’s quite plausible one could get the same results in less time. For the purpose of this document I used the official program, because it was the most consistently studied.

Cost Effectiveness Analysis of MBSR

Both depression and anxiety are measured with a variety of clinical surveys. To estimate impact, I assumed that the top score on each survey caused a DALY loss equal to severe depression/anxiety, as estimated by the World Health Organization, and that a drop of N percentage points led to a drop of disability weight * N. For example, a drop of 8 points on an 80 point scale of anxiety (disability weight of severe anxiety: 0.523) causes a gain of .0523 DALYs.

For a survey of papers showing potential impact, see this spreadsheet. The estimates range from 2% to 11%, clustered around 7%.

I have created a Guesstimate model to estimate the impact of MBSR. Results were quite promising. On a randomly selected guesstimate run, the average cost was $290/DALY, with a range from $43/DALY to $930/DALY. This is close to but better than Strong Mind’s $650/DALY and overlaps with estimates of antimalarial treatment ($8.15-$150/DALY). Note that the MBSR estimate may understate the impact due to systemic biases in how DALYs are calculated. However it may also overstate the impact, as medical studies tend to overstate intervention impacts for a variety of reasons.

The model makes no attempt to account for co-morbid disorders. Individuals with depression and anxiety would likely see higher benefits, since the same hour of meditation would impact both.

This model makes the rather optimistic assumption the benefits persist for life. This assumes that the participant would have been counterfactually depressed forever without treatment. In reality the average depressive episode lasts six months, and of people who have suffered at least one episode, the average lifetime number of episodes is four. If we assume the participant gets two years of benefit out of treatment the cost becomes $1200 to $14,000/DALY, with an average of $5200/DALY.

Caveats

All of the effectiveness studies cited were done on developed world citizens with only mild to moderate mental illnesses. Most were middle aged, and access to MBSR implies a minimum SES bar. It is possible that more severe depression is not amenable to MBSR, or that it is amenable and shows a larger absolute change because there is farther to improve.

I could find no studies on MBSR in the developing world, although since mindfulness meditation was originally created before there was such a thing as the developed world, there is a higher than typical chance that its usefulness will survive cultural translation.

All of the studies referenced had small sample sizes. They all show a consistent effect, but it’s possible publication bias is keeping negative studies out of view.

Official MBSR has an unusually high time cost compared to medication and therapy. The costs are high both upfront (eight weeks of classes and an all day retreat) and ongoing (one hour of meditation/day). Some patients may be able to get the benefits of MBSR with less time; others may not be able to practice at all due to the time demands.

For more on this see my shallow review of mental health .