Recently my 70 year old dad, stopped cutting his fingernails on one hand. The nails are longer than what my mom has. My dad is not alternative nor has demonstrated this behavior before. What was really unsetting is that he had an outburst with my sister recently in which he yelled at her "What if I take these nails and dig them into your face?" This is behavior he has never demonstrated before. He struggles with SADs and depression but this is really extreme and scary. Any thoughts would be appreciated. I guess I have gotten so used to his physical health going downhill that I haven't thought of his mental health.