How do you go about having conversations with people like this?

Say for example, the topic of mental disorders came up and someone who went to school for psychology basically takes over the entire conversation by discrediting everything you say just by saying “That isn’t right, you’re wrong. I went to school and studied this.” And “That’s not true, that’s not correct.” Like, they have a rebuttal for everything you say because they studied mental disorders in its entirety.

How do you go about having conversations with people like this?
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