Objectivists maintain that whether someone is mentally disordered is determined by facts about the individual.

Subjectivists maintain that whether someone is mentally disordered is determined by facts about whether their behaviour is judged to be inappropriate / unwanted etc.

Wakefield attempts to carve a middle way between the objectivists (realists) on the one hand, and the subjectivists (social constructionists) on the other. He maintains that there are two individually necessary and jointly sufficient conditions for mental disorder.

1) Malfunctioning mental mechanism/s within the individual (objective condition)
2) The effects of the malfunction/s are judged to be harmful (subjective condition)

He attempts to cash out the notion of 'malfunction' and the related notion of 'function' in such a way that it is objective (is not dependent on normative / subjective judgement). In doing so he appeals to work by Neander and Millikan on naturalising biological function.

A is followed by B (at least some of the time)
B is beneficial to the organism
Due to the process of evolution by natural selection...
The presence of A can be explained by the beneficial effects of B
And hence B is the biological / natural / proper function of A.
(Or A has the proper function of producing B)

E.g.,

The heart has a variety of effects.
It makes thumpity thump noises and it pumps blood, for example.
(A is followed by B and A is followed by C)
If hearts made thumpity thump noises but didn't pump blood then the organism wouldn't be around very long, however. If hearts pumped blood but didn't make thumpity thump noises then the organisms would be okay. Because of this we can say that while the heart has a variety of effects the proper / natural / biological function of the heart is to pump blood. The notion is that that is what hearts have been designed to do by the blind forces of evolution by natural selection.

Evolutionary psychologists typically assume that the mind is composed of different mental mechanisms and these mental mechanisms have evolutionary functions. Wakefield thus thinks that evolutionary psychology is the right science to tell us whether there is mental disorder or not.

What do people think about this?

E.g.,

Wakefield, J. 1992 'The Concept of Mental Disorder'. American Psychologist 47: 373-388

Wakefield, J. 1992 'Disorder as Harmful Dysfunction: A Conceptual Critique of DSM III-R's Definition of Mental Disorder' Psychological Review: 232-47

Wakefield, J. 1996 'Dysfunction As A Value Free Concept' Philosophy, Psychology, and Psychiatry 2: 233-246

Wakefield, J. 2000 'Spandrels, Vestigal Organs and Such: A Reply to Murphy and Woolfolk's "The Harmful Dysfunction Analysis of Mental Disorder' Philosophy, Psychology, and Psychiatry 7 (4): 253-269