Informal way to say "contrary to popular belief"?

Example:

Contrary to popular belief, depression is more about 'hows' than 'whys'. And sometimes we even use logic to try to justify it.

I think contrary to popular belief is too formal. Is another way of saying it? (I thought about phrases with unlike, but I think that word is kind of formal, too).

Solution 1:

Maybe something along the lines of

Despite what (many) people (often) think/assume/believe

e.g.

Despite what people think, depression is more about 'hows' than 'whys'. And sometimes we even use logic to try to justify it.

Solution 2:

How about:

Most people don't know this, but depression is more about 'hows' than 'whys'. And sometimes we even use logic to try to justify it.

Solution 3:

Perhaps it's nothing but an urban legend (also urban myth)

A humorous or horrific story or piece of information circulated as though true, especially one purporting to involve someone vaguely related or known to the teller.

Oxford Dictionaries Online