first and foremost, make sure that she gets enough nutrition. Lack of nutrition can cause depression.

Lack of sleep can also cause depression. Insomia can be caused by lack of water. Make sure that she drinks at least 8 or more glasses a day.

Thirdly, hormone imbalance. If she's near her meopausal stage thats normal. evening primrose oil can help. NEVER take synthetic hormone replacements or HRT as they have been proven to cause cancer later.