Mackenzie Phillips believes she had ` ` genetic predisposition '' to substance abuse . `` Certainly , it lent to the problem , but it was n't the root of the problem . '' Dad showed her how to smoke joint when she was young , she tells ` ` ' '' show . Drug abuse forced her out of role on successful CBS sitcom ` ` One Day at a Time '' Watch Mackenzie Phillips on Larry King Live , Wednesday 10 p.m . ET .
Mackenzie Phillips believes she had ` ` genetic predisposition '' to substance abuse . Dad showed her how to smoke joint when she was young , she tells ` ` ' '' show . Drug abuse forced her out of role on successful CBS sitcom ` ` One Day at a Time '' Watch Mackenzie Phillips on Larry King Live , Wednesday 10 p.m . ET .