Many medical conditions can affect mood, mimicking bipolar disorders. It is important to rule out these conditions before making a diagnosis. They include:
Hypothyroidism. Thyroid dysfunction has been known to affect mood and can cause depressive episodes.
Brain tumours, especially ones that involve or compress the amygdala, which is the region of the brain that decides your mood, can cause similar symptoms.
Neurological infections such as Lyme disease, HIV or syphilis should be ruled out based on associated symptoms and signs.
Treatment history of a high dose of steroids, medications for tuberculosis or HIV, have been reported to affect mood.
Vitamin deficiencies, especially vitamin B12 can cause neurological deficits and affect mood.