Hey. First off, I can definitely relate to what you're going through. I've also had pretty minimal results with the handful of medications I've tried, and have found DXM to be a very powerful anti-depressant. I haven't taken DXM in some time, because I started taking it fairly regularly in low doses as an anti-depressant, and inevitably developed a huge tolerance. But before then, I definitely found DXM to be a very useful tool for exploring the depths of my psyche, as well as a profound connectedness with the world. (not to mention some fantastic creative endeavours.)
In terms of the two medications your doctor suggested: Abilify.. if it's giving you more dopamine then it should have no interaction with DXM. I believe DXM is an SRI and will increase serotonin directly but not dopamine. (I also take Wellbutrin, an NDRI, (norepinephrine-dopamine reuptake inhibitor) and haven't found that it interacts with DXM expect for perhaps at high doses (my medication may indirectly increase serotonin) - but nothing like serotonin syndrome. The worst I've got was an increased heart rate but nothing dangerous.
If you were to go with the Celexor though, it being an SSRI, you may not be able to take DXM anymore, or at least make sure you exercise caution. I was on an SSRI a while back and was taking 5-HTP before bed to help with insomnia. As 5-HTP is a precursor to serotonin and makes more serotonin available in the brain... I definitely experienced an interaction between the two and was unable to sleep a few nights due to a racing heart. I assume DXM would interact similarly if not more intensely.
So if it's between the two I would choose Abilify. I agree with you that mainstream antidepressants such as SSRIs are often useless. They've done some recent meta-studies on the effectiveness of SSRIs as antidepressants, and something like only 1/3 people find relief from them. The Wellbutrin I'm taking has definitely helped me somewhat though, while SSRIs did nothing for me. You could also ask your doc about that.
One last thing and I will quit rambling. Because I have found DXM and ketamine (both NMDA-antagonists) so effective for me (and apparently others) as anti-depressants, I've done a lot of research in this area. A lot of studies are currently being done on ketamine as a very effective anti-depressant to those with "treatment-resistant depression", as well as a couple of other drugs that fall into the same category. Anyway just thought I'd share that.. posted a couple of links below. If you just google "ketamine/ dxm/ nmda antagonist + depression" a lot of links come up. I hope that within the next couple of years some of these drugs can be put on the market. Seems like it could be a massive turnaround in the field. Anyway, best of luck to you.
http://healthland.time.com/2012/10/...-most-important-advance-in-field-in-50-years/
http://www.medscape.com/viewarticle/805416
http://www.nimh.nih.gov/news/scienc...y-lifts-depression-without-side-effects.shtml