Birth control pills, which suppress the production of certain hormones in the body and often cause symptoms of menopause, can also cause foggy brain and memory issues. (mindbodygreen.com)
Do you know why I would get dopey / foggy brained when I take it? (westonaprice.org)
However it is also very common in cases of depression, fibromyalgia like muscle aches, gastrointestinal dysfunction and even foggy brain. (thehealthyhomeeconomist.com)