I read that changing from Effexor to Prestiq can be difficult. Some people complain they get too many side effects from the withdraw. Nausea, more depression, etc. Seems going from Prestiq to Effexor would be better. Effexor XR is better than Effexor. With your depression, if you have problems with energy, physical motivation, lethargy, you may like Prestiq better, especially at 100mg. Start at 50 then go to 100, maybe after 2 weeks. You might want to consider a slow with draw from the Effexor 225 to 150 to 75 to 37.5. The doctor will need to supervise the plan. My clients have done pretty good with Prestiq 100mg in the morning and Klonopin (anti-anxiety) two a day  and one at night, .50mg . Some people don't get side effects from dropping a medication. If you don't, you could transition to Prestiq quicker. I wish you best of luck. Depression is difficult to treat. Therapy along with the medicine helps. Do more research on these medicines so that you are ready to discuss medication plans with the doctor. Sometimes doctors want to augment antidepressant medicne with antipsychotic medicine like Seroquel, Abilify, Risperdal. Be careful with these. Some cause problems with sleep and some heavily sedate. THere are other medicines like Effexor and Prestiq. Cymbalta, Wellbutrin (these are SNRI meds) Prozac, Paxil, Celexa, Zoloft are SSRI. SNRI deal with Serotonin and Norepinephrine (more for those needing energy); SSRI work with Serotonin.  Read, research and don't give up. You will find a medicine that works. My client has relatively few side effects from the Prestiq.