It does make me wonder. It's possible she has a psychotic illness, like schizophrenia. But schizophrenia is a relatively rare illness. Drugs can also cause psychosis, including marijuana. The other possibility, though, that we shouldn't dismiss is that she wasn't psychotic at all and her strange behavior and paranoia was legitimate fear. Any (or all) combination of those three is also possible. Very sad cases of people with underlying mental illness being gaslighted or made to look "crazy" to others and in some cases, the victims are hospitalized because their perception of their lack of safety is thought to be psychosis.
Hope we find her and get some answers.