Hey Sable, I am sorry about your situation. Perhaps I am pointing out the obvious, but you just achieved something. You wrote a post and people are reading it. Keep 'em coming!

What’s more interesting is that I just switched medications from one that successfully managed the depression but not the anxiety to one that successfully manages the anxiety but not the depression

May I ask which medications?

Are you interested in receiving any advice from someone who used to have OCD/GAD but now lives with almost not enough anxiety?

Nice, these are interesting descriptions!

The inertia metaphor for depression is interesting because dopamine is associated with both mood and movement. So you see dopamine deficiency in mood disorders like depression and movement disorders like Parkinson's disease or restless leg syndrome. When you’re depressed and it takes enormous effort to move each muscle, that might be your brain searching for sources of dopamine because the usual sources aren’t working.

I’ve personally had the experience of lying motionless on my bed because I felt like I had exhausted all my options and I couldn’t see anything beneficial to do about my situation. It almost feels like the energy that would let me get up has been sucked out, and my body is just limp. I think in times like these, my brain isn’t able to find a promising action to take, and so it can’t find a source of dopamine to generate movement.

If Scott Alexander is right that depression is a “trapped prior on low mood”, maybe the brain rejects options that would produce dopamine because that would disrupt the expected low mood, which would be surprising and uncomfortable. So we actually maintain the conditions for low mood because our brain thinks it’s necessary in some way.

If there’s a non-chemical way to combat this, I think it’s by finding the cause of that prior and working with it until the brain is convinced it no longer has to maintain the low mood. I think that’s what therapy, meditation, or lifestyle changes are actually doing when they work. The brain gets enough evidence that the low mood is unnecessary, and it stops expecting it.

In my case I noticed that I was punishing myself with negative emotions because I had high expectations that I wasn’t meeting, and I felt like I could transform myself into that ideal if I just felt sad enough. Over time I gradually convinced my body that this didn’t help, and that I was more productive when I let myself relax into a kind of neutral, default state. This involved going back and forth many times between a low baseline and a neutral baseline until my body decided the neutral baseline was better. When my brain wasn’t automatically rejecting every plan I came up with, then I found I had plenty of energy and motivation.

But that’s just my model of how it happened, and I don’t expect my experience to replicate for everyone else.

Interesting! Thanks for sharing. What you describe as inertia sounds more like apathy to me than depression. But rather than a comfortable pillow which resists attempts to move it, it feels more like there's nobody home in my body. I say "Move" but there's nobody to hear, nobody to care. There's no feelings, just the last bit of rational thought going "huh, that weird, something seems to have broken."

Right now I'm feeling that "meh" at everything, just barely excluding the things that I need to stay alive. So by your description, I'm currently depressed, but my mood is strangely alright.

Depression to me changes my worldview entirely. Reality gains substance, it feels much more real, less superficial. The world becomes much larger, more serious and heavy. It feels cold, lonely and dark, even around people, in warm places, and with my face right next to a 1500 lumen LED light.
I'm fairly sure that my vision actually loses some of its color, and even strong people seem pitiful and weak. Another interesting note is that my 'territory' shrinks. My environment, even my own things, become hostile and unfamilar, rather than tools which are mine to manipulate for the sake of my goals. I don't feel sad when I'm in apathy, but I feel terrible when I'm just depressed. Just awful. At times I'd have a "good day" and only score mild to medium on the depression scale, and feel like that level of negative emotion wasn't even worth mentioning. It's like going from passing a kidney stone to having a mild headache.

Anxiety feels like standing at the edge of a cliff, or like there's a sword hanging in a hair above my head. There's a sense of impending doom, confusion, and the feeling that I'm forgetting something important. And everything feels fragile, I get this sense that everything is decaying right before me, that it can break at any moment, that everything is scarce, rare, limited.

I like depression more than anxiety, until the depression gets bad enough, anyway. I think the two blend together at some point. When I'm a bit depressed I might casually think about suicide, but when I'm even more depressed, the idea of suicide becomes extremely scary. It suddenly becomes all too real. Like I'm forcibly immersed/grounded in a nightmare or psychological horror. But the worst of them all for me is apathy. It's worse than suffering. I have very little respect for nihilistic philosophies.

By the way, in Nietzsche's Zarathustra he talks about "the spirit of gravity" and about how you kill it with laughter. When he says "I could only believe in a god who could dance", what he means is a god who is light on the feet, i.e. "above" that gravity. The book feels a bit like it was written by somebody with mood swings, moving between depression and hypomania. From "Forgive me my sadness!", forgive me that evening came!" to "Now a god dances through me".

Really interesting! (and, just as everyone said: kudos to you for having written an interesting post while anxious and depressed :-) ).

But I notice it makes me confused. I used to be depressed (although I should probably say ‘used to be in a depressive episode’, these things never 100% go away, do they?), then my depression got better, but there still was/is weird stuff going on with my mental health. No longer being glued to my bed by despair, I called it anxiety rather than depression, but now I’m not so sure anymore?

Of course, my depression clearly looked like a depression: can’t get out of bed, why would it matter anyway, what on Earth is wrong with me, etc. (NB: what you say fits well with the point I’m trying to make here, but I’m surprised that the only thing you say about metacognition is that you don’t do much of it. First because writing a blog post on what’s going on in your brain probably counts, and second because imho overthinking about your mind is imho a big part of the experience of being depressed, something also described very well by this guy.). 
Then I got better: I made more friends, took a few steps to get to do less depressing stuff, got involved in a couple of cool projects, etc., etc. 
Not being very sad all the time is good for you, 10/10 recommend. 

So, I’m not depressed anymore. And yet, when I go to my therapist, it’s to say stuff like ‘Inertia is blocking me from doing stuff, I need to feel more motivated, I want to procrastinate much less, my behaviour is clearly not goal-directed enough, etc.’. If it were just anxiety, I would indeed have a similar behaviour in the sense that I would focus on ‘safe’ activities, but why would I then spend so much time feeling terribly anxious about my inability to go beyond those ‘safe’ activities? 
 

I suspect that, at least in my case, it started with the anxiety (‘I feel like I can’t do this thing, or that thing, or that other thing’ – interesting to note that it’s rarely obvious what exactly I am fearing, although it’s often easy to tell when thinking about it), the anxiety caused inertia (‘well, if I can’t do it well, why bother’), and then the depression came from that? I am not sure this actually makes any sense. Probably the root causes of something are to be found in the symptoms of ASD: executive function and social cognition issues => belief that I’m crap at dealing with social situations or working hard, anyway. But I’m not sure where exactly that would fit, either.

Anyway, like I said, great post!

I appreciated the distinction you make between anxiety and depression and can see that in myself, but had not previously made the distinction. I'm wondering now if that might help with addressing problems of procrastination -- that seems to be something of a symptom. Perhaps looking into why I am procrastinating to see if it fits more with a depression mood or anxious mood might help overcome the inertia.

Been there - well not exactly the same but depression, panic attacks, all that, yes a long time. Try a mixture of patience and looking at your fears.

If the fear is too big, don´t look. Try existing, try doing something nice or even something necessary and concentrate on that.

Try looking at your fear again.

What is the worst that can happen? You fear beeing overrun by a car?

Your fear is solid, don´t try to fight it with bravery, just train yourself to be EXTRA careful.

You fear you could fall into a thorny bush by the wayside? Go that way anyway, fight your fear with bravery at a time you have the nerve for it.

Perhaps take a tetanus shot before.

Have a lot of patience with yourself.

Still fighting myself.

I am proud of me. I had a long fight. I exist. And at the moment it is even fun existing!

Tomorrow - who knows?

Finding your way between scylla and charybdis, be proud of yourself.

Great post! Is 

Gravity only applies to those who don’t look down.

possibly a typo? Based on the context and video It feels that you might mean "Gravity only applies to those who look down."

Both gravity and inertia are determined by mass. Both are explained by spacetime curvature in general relativity. Was this an intentional part of the metaphor?

These are really good descriptions! (Going by my own and friends' experience). For me I might just tweak it to put anxiety as the height rather than the gravity. Thank you for writing these up!

Thank you for writing this - it's a really useful and accurate view, I think. I too deal with both of these mental bastards and you're right, it can be hard to see them separately; but this is almost exactly how it is for me too and I'm glad you shared it.

Reading this also made me have a bunch more thoughts about monotropism, which I've been studying with great interest lately. The depression physical movement thing you describe (which yup, hard same here) feels like it must be related to my high monotropism somehow, and I'm looking forward to looking into the link more. (You may look monotropism up if you're interested, but i just wanted to share that your post gave me a good lead on a useful idea, which i appreciate!)

Just curious, how related do you think your symptoms are to social interaction?

Though they have very different methods, both anxiety and depression tend to have the same result, at least for me: I don’t do anything.

This reminds me of the post I wrote about my own depression: https://chipmonk.substack.com/p/depression-was-useful 

Thank you for sharing this. I'm sorry that anxiety and depression continue to haunt you. I've had my own, less extreme, struggles, so I can relate to some of what you wrote. In my case, I was lucky enough to find some good personal development resources that helped me a lot. One I might suggest for you to check out is: https://www.udemy.com/course/set-yourself-free-from-anger/. You can often get this course on sale for <$20. From what you've described, I think the "Mini Me" section might be most useful to you. Hope this helps you in some way.