All I can tell you is what happened to me. It's been so long ago now that I hardly remember. I think I've been on paxil for over five years.
I do not remember if starting caused weight gain. What I do know is that I feel so much better.
After 4 to 6 weeks, I realised that I had the oomph to do all the things I needed to do. I was back "into" my hobbies. I wasn't struggling to make myself go to work. I was humming and singing. I was interested in exercise. I enjoyed food shopping.
My doctor told me I was a poster child for SSRI's. Because paxil worked, he knew I had the chemical imbalance that can be treated with them.
I still have reactional depressive episodes. Almost everyone does. Life sucks sometimes
If I became overwelmed, I would go back to my doc. But, as a rule, my mood does lighten (maybe slower than most folks) as I work away at troubled times.
It's kind of like this ... I (with my chemical imbalance) seem to sink deeper into the mire of depression than "normal folks" and can't seem to pull myself out.
With my medication ... the playing field is more level. I react more like "normal folks" do. Does that make sense?
Now about the weight thing. I'm about 90% certain that without my meds, I could not do the things I have to do to stay healthy. My choices would be bad, my thinking not logical ...
On my medication, I feel good enough to do what I have to do.
Does the paxil make it harder? I have no way of knowing.
Did I gain weight at first? I don't remember.
Me, my disorder and my paxil are a unit now. And we are losing weight.