ThatBritGuy:

Our definitions of mental health are entirely behavioural - i.e. the ability to hold down a job (if there is one), have relationships, and not say odd things about mind probes and TV aliens from the sofa.

The fact that one of the diagnostic criteria for "disorders" is "suffering distress" lends credence to the view that many "mental disorders" are social. That is, if the social environment is such that the "subject" doesn't experience distress, it's not a "disorder". Then, whose problem is it, the "subject" or society's for not being accommodating?

Example:

Autism Spectrum Quotient - Wikipedia, the free encyclopedia

although the test is popularly used for self-diagnosis of Asperger syndrome, the authors caution that it is not intended to be diagnostic, and advise that anyone who obtains a high score and is suffering some distress should seek professional medical advice before jumping to any conclusions.

...

Of the students who scored 32 or more on the test, eleven agreed to be interviewed and seven of these were reported to meet the DSM-IV criteria for Asperger syndrome, although no formal diagnosis was made as they were not suffering any distress.

(My emphasis)

So mental illness is to a lerge extent social. In the social environment of his mother, Sven's friend will suffer distress and cause it on others. You can call it mental illness or not, but the fact remains that a different social environment would go a long way towards removing the distress.

Keynesianism is intellectually hard, as evidenced by the inability of many trained economists to get it - Paul Krugman