Any long term use of antidepressants causes the brain to 'down-regulate' its own production of serotonin and other neurotransmitters causing the patient to become 'acddicted' to the drug.  If the patient tries to stop taking the antidepressant it can take many months, even over a year for the brain to regrow the atrophied parts of the brain necessary to product adequate serotonin without the drug.  Doctors are MISTAKING this effect as the patient 'needing' the drug or of 'relapse' of depression.  This is WRONG.  The drugs actually CAUSE depression and anxiety in patients through the withdrawal process.  Don't be fooled!  Many thousands of people are being misled that they 'have to' stay on these medications because when they try and get off they experience horrible withdrawal effects.  Pharmaceutical companies are NOT telling people the truth.  The brain is NOT a static organ.  It rebuilds and modifies its neurons and dendrites and connections from day to day, week to week, month to month etc.  There is NO SUCH THING as a 'permanent' chemical imbalance.  Fix the dysfuctional thinking patterns and bad environment and the brain heals BY ITSELF without drugs.  This has been proven through studies of neuroplasticity and neurogenesis.   Drug companies are only interested in your money...not your well-being.   Doctors are bring misled and mis0-educated by pharmaceutical companies who make BILLIONS of dollars from scaring you into taking these drugs.  It is all about fear.  Don't be fooled.