First, on the MRI scanner as treatment. As you may know, there is a technique called rTMS, repetitive Transcranial Magnetic Stimulation, that's been under research for at least 10 years. It is perhaps close to getting FDA approval as a medical device for treatment of depression (a third try at this is underway). I was getting very serious about buying one of these devices, about $20 - $25,000, worth, when the Mclean study you linked came out.

The rTMS device has to be used in a fairly specific way, a certain location on the skull to stimulate just a certain portion of the frontal cortex, at a certain rate: thus duration of stimulation, position, intensity have all been studied, although that work is still going. All of a sudden, comes the Harvard report (I like this story because apparently a radiology technician basically got the idea for the study when he observed that people coming out of the scanner seemd "happier" than when they went in, and it's not the kind of experience (a little tube to lie in for 20-30 minutes) that you'd think would have that kind of effect. What I like about the story is that the research doc's listened to the tech person! So, they took her/him seriously and designed a study to test this observation, and sure enough, they got a very strong result).

The irony here is that the Mclean result was so strong that it has derailed, for me at least, the move toward rTMS. The TMS magnet requires some skill to use, and having too strong a pulse has caused a very, very small number of seizures (7 in all the research done so far; none since the researchers started using 20 hertz as a maximum strength). So if there was a simpler way, that would be much better (TMS can cause some headaches as well but is otherwise apparently otherwise completely safe, according to results thus far; of course, long term repetitive use has not been studied -- for TMS or this newer McLean-based approach). So, I've shelved my plans to buy the rTMS device as a result of this McLean work.

The really puzzling part is that the rTMS work is based on stimulating the brain in a very focused area, whereas the McLean approach stimulates the whole brain, although at a much lower energy level. So, there is going to be some serious work to be done figuring out which approach is better, as well as just how they work in the first place, if the smaller device the McLean team is going to test turns out to work like their big scanner did.

Finally, note that the scanner is not your average MRI rig; this was MRS, magnetic resonance spectroscopy, and the settings are different. I'll have to ask on of my radiology colleagues if the entire device is different; certainly the software is, but that wouldn't really matter if the magnet is the same or can be made to function the same. I certainly understand the appeal of the simpler device for patient care. This is going to be interesting (including the debate -- can you imagine? -- about who's eligible to get this treatment; i.e. what happens if people want to use it to just cheer up a bit on a bad day, for example?)

Secondly, there's the use of MRI diagnostically. To be brief: "not there yet", nor even close as far as I know; and we could wonder whether it would be a good thing if it could be done, as this is a very expensive way to get to a diagnosis for a condition that is very common, and we're already spending too much in medical care generally, (including on tech' tools like this) and too little on mental health treatment.