Buspar and Lorazepam are anti-anxiety drugs according to my nursing hand book for drugs, not antidepressants.
Effexor is a drug approved for depression, generalized anxiety disorder, and social anxiety disorder. It is used off label for several other things including pain management
Effexor works in a completely different way than your drugs do. I looked up the side effects that you are concerned about. According to my book it causes anxiety in 6% of patients using it, and agitation in about 2% of users. It also actually caused somnolence in 23% of users and insomnia in only 18%, so you may get lucky and be one of the people it makes sleepy. I took it years ago and it gave me no side effects at all except a bit of constipation. No suicidal thinking either.
The warning about suicidal thoughts in my book says they usually happen when the drug is first started or when dose is increased. Since you have had them before, call your doctor immediately if they occur, and be sure and let another adult know you are starting it, and that this is a side effect if you decide to take it.
Effexor is an SNRI, it increases two neurotransmitters called norepinaphrine and serotonin. These neurotransmitters are involved in carrying both mood and pain signals to the brain. it is thought that by increasing the amount of these neurotransmitters, your pain levels may go down.
Often with antidepressants the dose for chronic pain management is much lower than that for depression. Because of this the side effects one gets may also be less. The percentages I quoted earlier in this post may actually be far less for folks on low dose therapy for chronic pain.
The dosing for depression is as high as 225-375 mg. per day. I never went higher than 150 mg. per day in two doses of 75 mg. each morning and night.
If you feel strongly about not taking this, don't take it. It is up to you. There are other choices. But, I am willing to try most things once and cautiously.
Antidepressants don't work for me, I tried most of them, the side effects of most were not worth the little benefit for me. I take antiseizure meds instead. But we are all different, and what works for me, may not work for you.
Take care, Annette