Some drugs that relieve anxiety or depression can also cause or exacerbate glossodynia symptoms. However, I can't be sure without knowing what drug or combination of drugs she was taking. She should find out the names and dosages of all her medications and ask her doctor or a pharmacist about drug-drug interactions, side effects or drug reactions. Also, your wife should know that glossodynia is sometimes a sign of emotional upset or mental illness itself. Some researchers even suggest that there are two categories of glossodynia, one with medical origin and another with a psychological origin.
Treatment is different for each category.
From your letter, I get the sense that your wife stopped taking the medication for depression. I hope she stopped only after consultation with and approval of her doctor or doctors. Your wife may want to undertake some detective work on her own to try to find the cause of the burning and painful tongue. She may also want to experiment with using different brands of toothpaste, mouthwash or chewing gum. If she smokes, she should stop and see if that helps with the pain.