I experience dizziness on and off. sometimes with a headache and others with nausea. been seen by a neurologist who believes this is due to my lifelong anxiety + insomnia issues. worried as dementia runs in my family. should i have a brain mri?

Family history of dementia and your current symptoms are unrelated. However, with those symptoms and you never had a CT or MRI of the brain done in the past, I would like to have one ordered.

Suggest you now focus on your lifelong emotional and sleep dysfunction issues, and handle your fears proactively. Urge cognitive-behavioral therapy, possible biofeedback, and acupuncture in addition.