My sister who is a very mean, vindictive, poor excuse for a human being wanted to "get even" with me for an family disagreement in which almost everyone sided with me about! To get back at me she told all of our mutual friends about my mental health history! As a result I've stopped being invited to parties and other events and activities and was even un-invited to a wedding! Can I sue her in civil court for slander - as I have found that a lot of what she said is absolutely false and has ruined my reputation with these long-time "friends"! Thanks!