My Mother in law has been on anti depressant drugs from 1998 - The medications she had were - Repoise, Amixide, Qutan, Cipralex Lifodep, Rivotril etc Lonazep, - Now currently she is taking the following medicines - Venla 75, Lithosun 300, Cipralex and trapax . My question - Are antidepressant drugs taken continuosly fo more than 15 year effect the nervous system and are they harmful. Do patients become immune to the medication after a period of time