I was using sertraline75mg for more than one year.

Hon, your post isn't clear to  me. Are you saying you came off sertraline after a year and "relapsed" with the condition you were put on it for?  How did you come off of it?  This is important, because if you come off too fast from these drugs, even over the course of six to 8 weeks, it is too fast and will have withdrawal symptoms that seem like the original condition.  Not all of us can come off these drugs and have "withdrawal" end within 6 weeks, which is what doctors tell you it may take and that anything beyond that is "something else."  Simply not true.  There are people who were put on ADs for something other than anxiety and depression, such as chronic pain or PMS, and then have anxiety and depression in withdrawal.  This is an important distinction because it means you are likely NOT sick again though it may seem the same (usually worse).  Some of us just have to go much slower than that to succeed in getting off the meds after they have done their job.  Trust me, you don't need to be on these meds for years but that is what will happen if you go on the medi-go-round.

It is perfectly safe to do a straight swap from sertraline to venlafaxine without cross tapering or having a drug free period. The best thing to do is bite the bullet and start taking the venlafaxine. I did this swap and I was prepared for some side effects after what I'd read but actually had very little issues at all. Mild headaches for a few days and that was all. In fact I felt a lot better on the ven within 5 or 6 days! I wasn't lucky enough to be given an enzyme test so my change was a "try and see" and was plain sailing...

When increasing later on (I'm now on 225mg) I had headaches and heightened anxiety but that only lasted 3ish weeks Hope that helps xx

I was in setraline for 3 years then it stopped working,tried many others but ended up in hospital,I had ect and was prescribed venlafaxine ,it really helped me,I'm now weaning off it,on 37.5 mg at the moment