Saturday, April 23, 2016

The gap between neural circuits and understanding people

A new Personal View in The Lancet Psychiatry goes overboard trying to create a taxonomy of brain circuit dysfunctions in depression and anxiety. It suggests 6 neural circuits have been implicated, viz. default mode, salience, negative affect, positive affect, attention and cognitive control:-
Accepting such circuits have been established, eight biotypes of circuit dysfunction in depression and anxiety are then suggested, viz. rumination, anxious avoidance, negative bias, threat dysregulation, anhedonia, context insensitivity, inattention and cognitive dyscontrol:-
It's even suggested how neural circuits might relate to treatments:-

I think what's being proposed is that the precision psychiatry of the future will identify apparent brain circuitry dysfunction and treat on this basis. I guess it won't need to interview patients. The article is certainly a tour de force of imagination, but does it relate to the real world?

As I keep saying, mental function is not well localised in the brain and I'm not sure we've really identified any more localisation of function through identifying the so-called brain circuits mentioned in the article, even if they are valid. As I said in a previous post, "It's a long step to mapping specific mental illnesses to dysfunction of brain circuits". The article suggests that people like me that believe that mental disorders are not brain disorders, which the article concedes, surprisingly, is the typical view, have a "limited understanding of real-time coordination in the brain”. I don't think this is the case and the article at least recognises that a lot of money has been spent through the RDoC project (see previous post), the White House's Brain Initiative and DSM-5 (see eg. previous post) to prove me wrong without success. 

The language about brain circuits cannot be incorporated into clinically meaningful taxonomies because, although mental phenomena have a biological substrate, that substrate cannot tell us the meaning of mental phenomena. The psychiatry of the future will still have to interview patients to get them to tell their story. We can't see that in a brain circuit.

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