If you rewire your brain, what happens if you miswire? For example, you join a cult

The idea of rewiring your brain, neuroplasticity is popular.  One TedX video on changing your brain is this one by Barbara Arrowsmith Young.

But how do you know you are rewiring the brain in a good way.  Are you miswiring the brain?  Like how.  Like if you choose to join a cult as described in this TED talk.

Changing how your brain works is possible, but who do you trust to rewire your brain?