I've been chronically depressed for the last 25 years. During that time I have meditated off and on, with variable results. I've found that my depression was heavily biological, meaning that it was greatly influenced by diet, exercise, and other physiological factors, and fairly resistant to psychological therapy. I restricted my carbohydrate and gluten intake (adopting a "primal" diet), and I established a regular exercise routine of running, yoga, and hiking. Now my meditation is much more rewarding than it was before, and possibilities seem to exist where there were none apparent before. There are quite a few books out there regarding the holistic treatment of depression. My personal favorite is "Healing Depression the Mind-Body Way", which is yoga-centric.
In general, I'd say that if I found a way forward, then anyone can, once they find a comprehensive approach that works for them. And don't rule out SSRI's--I found one to be very helpful for several years, allowing me to establish new routines. Fortunately, I no longer need it. Best of luck to you...