PRIVATE PRACTICE - "Mourning Sickness" - The doctors join together for a celebration at Addison's house and to reminisce about the past. Meanwhile, Sheldon counsels a suicidal patient who comes forward with a shocking confession, on the 100th episode of "Private Practice," TUESDAY, OCTOBER 2 (10:00-11:00 p.m., ET) on the ABC Television Network. (ABC/CAROL KAELSON) BRIAN BENBEN, BENJAMIN BRATT