What does that say, other than: that, in a modern sociological environment, certain genetics-mediated brain differences cause people to behave (react) in different ways to their environment?

It says nothing about what inherently is a mental disease and what is not. Perhaps genetic differences causing certain mental "diseases" in average American society (or whatever society in which you conduct a study) actually benefit the individuals in societies with different cultures or structures. In the same way that certain non-psych heritable "diseases" confer some advantages and disadvantages (sickle-cell anemia and malaria, for instance). Fact is, many genetic differences that some people regard as undesirable are not even classified as diseases, even though they have advantages and disadvantages, if not for lifespan, certainly in social mobility within social environments.

tl;dr: it's patently obvious and beneath discussion that in certain genetic differences might lead two otherwise identical individuals to differ on whether they have different behavior, just as they might differ in many other ways. It's the determination that different behavior in some cases is a "disease" that seems to be at the heart of Szasz's critique of psychology.

Yes, I don't understand how is this study conduced since the diagnosis for bipolar disorder is not conclusive itself.. It doesn't tell anything on how it's purported that the brain is 'faulty'

How do twin studies rule out "environmental" that is, non-genetic, causes. Twins look alike, so if there are ideas about how people who look alike ought to act alike we would be expect a correlation between genes and behaviour that has nothing to do with the content of the genes. Rather, that behaviour would be motivated by similar ideas.

> How do twin studies rule out "environmental" that is, non-genetic, causes.

http://en.wikipedia.org/wiki/Twin_study

I have pointed out that there can be correlations between genes and behaviour that are not caused by genes but by culture. Your link is irrelevant.

So thoughts, feelings, and behaviors are outside of biology? How does that work?

I realize that you are simply quoting a passage and not necessarily personally espousing what you wrote.

Just a note, I'm quoting that passage because I (and scientific evidence) disagree with it.

Thoughts, feelings, behaviours, and mental illness most certainly have biological bases, which makes Szalz's theories pretty loony.

Szasz entire screed appears to be based on mental illnesses not being able to be concretely diagnosed or detected, but then jumping to the conclusion that they are completely made up and abused by society to control everyone's behavior.

Once you "accept" his conclusion, it doesn't seem possible to be argued out of it until science advances to an arbitrary point where one feels it adequately explains mental illnesses. "accept" in quotations as I honestly can't tell if his supporters are trolling or honestly believe what they're posting.

You have admitted you don't understand Szasz's position, presumably you should be interested in finding out more, see: http://fallibleliving.com/thinkers/szasz and the reading list at the bottom.