Diabetes need not give rise to any symptoms in initial stages. Excessive sweating and itching are not classical symptoms of diabetes but diabetes can present with varying symptoms and is better to do fasting blood glucose than keep guessing about it. Depression can lead to diabetes indirectly due to overeating, inactivity and some of the antidepressant drugs increase the risk of diabetes. For further details kindly refer to http://diabecity.co.in/basics-of-diabetes-what-is-diabetes/