it depends personaly it has made me a better person and less depressed but sometimes when i smoke certain things will send me into a depressed downtime and being high and drepressed sucks!it depends on the person really it can help and it can hurt...becarefull if you think it is effecting her negatively then immeadiately take it away but i say go for it just be carefull with it most people like your sister tend to get depressed rather than happy