Whatever the cause may be (infection, deficiency, stress, trauma, or genetic) has certainly affected her at at psychological level. It may not be brain malfunction (serious) but it certainly is psychological. That's my belief.

Extract :
The brain and nervous systems have been designed by evolution to be designed by experience and learning. This means there is no prototype for how brains function that map directly on to psychological level processes, like an American high schooler being rejected in love and feeling down about that

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Some of these will involve suffering and maladaptive patterns that do require mental health assistance but are NOT in any way shape or form reducible to brain malfunction...