Dissociative Identity

Meet Morgan.
She's a normal 15 year old girl. Normal friends, normal family, normal school. Well, almost normal everything. Morgan has Multiple Personality Disorder, and has had it since she was four. Now, unlike other people affected by the disorder, she only has one counter part. Logan, the name her counter part goes by, is not your normal 15 year old. She is affected by Cocain, alcohal, and boys who could care less about her. She loves to destory Morgan from the inside out. While Morgan faces the horrors of being a teenager, Logan makes it worse. Morgan can hear Logan from her head, even when she isn't showing herself to everyone. Now, obviously Morgans' family knows about the dreaded Logan, but don't know what to do about her. Morgans' mother Joelisa watches helplessly as her daughter is sucked into a vortex in which escape is nearly helpless. What can anyone do? How can Morgan get rid of Logan without ultimately killing her own self?