It took me several years of trying different antidepressants to find that helped my depression. (I am bipolar but initially I was continually depressed more than manic).

A good doctor would evaluate the effectiveness of an antidepressant (some take several weeks to help) and if the med is not helping her mood then adjust the dosage or try another med. I am on several different meds.

When my depression was severe I would often sleep eighteen hours per day to avoid the world. At that time I did not think it would change.

Does she consistently take her meds as prescribed?

I don't know if Japan offers this but I was in Intensive Outpatient for a bit. Most of it was group therapy and meeting individually with a therapist once or twice a month. Most programs run four to five hours a day. Some people go five days a week but later cut back to one or two days a week as they improve. But again the question is will she get out of bed to attend the sessions.

Does she have a case manager beside her doctor?