One common cause of hyperprolactinemia is a growth or tumor on the pituitary gland called a prolactinoma. The tumor produces high levels of prolactin. These tumors can be large or small and are usually benign, meaning they are not cancerous. Large tumors can also cause headaches, vision problems, or both.
The most common symptoms of atypical antidepressant withdrawal, including Cymbalta, are anxiety and low mood, such as apathy and rebound depression. Because Cymbalta strongly affects serotonin, after discontinuation it can take several days for the body's own serotonin system to return to normal.
My daughter was put on 20 mg cymbalta twice a day, a week ago. Her side effects were nausea (first 3 days), heart beating fast (eating followed by walking up stairs--twice), and waking 4 times in the night (reported for two nights). She has never been on any sort of prescription or other drugs--not even aspirin.