What I have learned through marathon training so far is that running long distances is a true mind/body experience. As in, at a certain point both your mind and body (especially the legs) are screaming at you to STOP THIS NONSENSE IT IS INSANE. Then you have to somehow find the one small part of you (the David to your Goliath) that is willing to ignore both of them and carry on in the hope that at some point it will get better.
That's the other thing I've learned: you can be feeling completely trashed at mile 16, yet by mile 18 you'll feel like you're flitting weightlessly along on puffy clouds and rainbows. It doesn't seem possible, and yet it happens sometimes - that complete, rapid shift to feeling 100 times better than you did just a few minutes prior. Of course, sometimes it doesn't happen, but with the help of gels, water, mini goals (run to the mailbox... now run to the telephone pole...), and your running buddy, you get through it anyway.
Basically it's taken me approximately two months of marathon training to learn with respect to physical endurance what it's taken 2.5 years of therapy to learn with respect to dealing with depression/mental endurance: you keep moving forward knowing that it is going to get better. You don't know when - be it a mile down the road or 24 miles down the road - but at some point it won't be so hard. You just keep going. It sucks, you keep going. You puke, you keep going. You think bitter, evil thoughts about the drivers who don't understand crosswalk signals, but you keep going.
A difficult long run and depression are obviously not the same thing. If I had to choose between horrible, painful, 20-mile daily runs and daily depression, I would choose the running. No question. And while I *might* wish those horrible running workouts on my worst enemy under the right circumstances, I wouldn't wish depression on anyone. Ever. Because depression is like being in the solitary confinement ward of hell.
But. Sometimes now when I get depressed - and it does happen, frustratingly enough, even with the antidepressants and the running and the decent diet and 6-8 hours of sleep every night and the therapy - I try to treat my mind the way I treat it when I am struggling during a run. Which is basically to ignore the protests while giving it as much meager encouragement and positivity as I can muster, and by trying to distract it.*
It's not that simple, really, or at least it doesn't feel simple when things get bad. But I think this approach - ignoring the negative, saying nice things to myself (even when I protest), clinging to the belief that it won't always be so hard - is helping. I'm not saying it makes me feel good. Honestly, it doesn't. Depression is a deep pit. It's not like you can just launch into a standing jump and hop out of it. But treating depression like a difficult yet surmountable obstacle - as opposed to an insurmountable and permanent fate over which I have absolutely no control or any way to deal with - helps get me through, which at certain points is all I can ask of myself.
“Listen to the people who love you. Believe that they are worth living for even when you don't believe it. Seek out the memories depression takes away and project them into the future. Be brave; be strong; take your pills. Exercise because it's good for you even if every step weighs a thousand pounds. Eat when food itself disgusts you. Reason with yourself when you have lost your reason.” - Andrew Solomon, The Noonday Demon