A/N: I promised myself I wouldn't write for this fandom because I wouldn't do it any justice, but then this happened.

Depersonalization/derealization disorder, symptoms: feeling disconnected from one's physicality; feeling detached from one's own thoughts or emotions; feeling as though one is in a dream; feeling as though one's environment is lacking in spontaneity, emotional coloring and depth

It creeps up like a dull sound buzzing in the back of his mind, barely there, hardly significant. There are times and times, and it usually shows when they stay at home for several days in a row, killing time and waiting for a case. God, how he hates those days. They used to be unbearable because of the excruciating, mind-numbing boredom, but it's slightly different now. Something has changed.

One time, he spends the entire morning laying on the sofa while John is writing nonsense on his blog again and it's when he notices. He looks at the ceiling and the ceiling is not in its right place anymore. He shifts his gaze, inspecting the room, and there's something off about that, too. The objects. They're not right, they're not there. They're not his. They're farther than they should be. Sherlock extends a hand in front of his eyes. He spreads his fingers. He moves them, feeling every little motion in his nerves, but not quite. There is something wrong. His mind is doing something that he didn't give permission for. He doesn't know what it is. It's unacceptable.

'And what exactly do you hope to accomplish by that?' John asks matter-of-factly, not looking up from his laptop.

'Hm?' Sherlock asks. Oh, right. His hand. He must have been staring at it for an extended period of time. It's there, isn't it? Obviously. He should know better. He's seeing it, after all. It's there. He doesn't dignify John with an answer.

This is new; it's never happened before. It's a bit exciting, if not for the slightly odd sensation of detachment, but Sherlock's never been one for feeling, anyway. He tentatively takes a few steps around the room; he examines the wall closely and notes that how ever close he gets, the wall still seems to be situated a few centimeters farther than it normally would. The texture is the same, but it's unsubstantial. As if it weren't there. He touches it, his palm makes contact with the cold stone and he feels it, it's there, but not exactly. He tries again: the same. He recalls: he hasn't ingested any perception modifiers in the last twenty-four hours. He's eaten in the last twelve hours. There were even a few hours of sleep in the program, given the boredom and all. What ever this is, there was nothing concrete to trigger it, so it shouldn't be happening. But Sherlock knows that nothing ever happens without a cause. It's just a matter of time until he deduces it.

'Sherlock,' John calls again and this time he's actually eyeing him with a suspicious look.

'Yes, yes, I'm fine,' Sherlock dismisses with a wave of the hand, his gaze still on the complex, dull, tedious, fascinating colours of the tapistry: unreal. 'Go back to your stories, John.'

It's not like it was with the hound- no, not a hound, but a giant, hardly existent dog- see? (John sighs and abandons the lost cause. Good, he thinks.) There was a cause back then, hardly obvious, but not impossible to find. It had been one of his most difficult cases, actually, because his senses had been wrong (impossible). It happened again. He wasn't alarmed now, though. There was barely anything to fear- just reality. Reality, Sherlock had come to know, was nothing dangerous. Tedious in general, mildly entertaining at times, extraordinary on special occasions. Hardly perilous. He could figure this out.

Obviously, his mental faculties were intact; only his perception of reality was affected. Lack of in-depth field perception. Micropsia. Sensation of unreality towards the environment and towards himself. Symptoms; they sound like symptoms. Obviously; but for what? Clearly enough, it was only him who felt like this. Like a stranger inhabiting his body inhabiting a paper-fake world. I don't understand, John would say. Well, of course you don't, you idiot. I don't, how could you? (Don't worry, practically everyone is, he would add- he didn't mean it as an insult.) But no, he did. He had to. It was much too late to have an existential crisis, for God's sake. That age had come and passed and left Sherlock unperturbed. Well, not more affected than usual, if you count out the cocaine. Yes, cross that out. Sherlock knew that the world was real. He lived off the world being real. He got off on the world being real. At the present moment, the world refused to appear real. This was absurd.

He took a step, then another. He extended his hand forward, he tried to sense the movement. He sensed automatic, uncoordinated, habitual. He traced a deep trail with his fingernail on his left arm. The slight pain was there- it felt more real than a simple touch had, more substantial. Obviously, pain is a more intense sensation than usual proprioception. So the thrill, it was. This new condition was connected to lack of activity, to stagnation. Perhaps the world is so tedious that it started disintegrating for the sheer entertainment of it, Sherlock thinks and then he thinks, stupid.

He wonders where John left his gun- he hasn't used it in a few days. Left drawer. He retrieves it, aims around the room with undecided focus, sets on the wall that doesn't quite seem to be a wall. He takes a deep breath, he notices his state- detached, diffused, unreal. His hand lifts by its own accord- he shoots. Bang. The bullet hits the wall in something a bit more than slow-motion. John shouts something, Sherlock doesn't listen. He breathes. He feels alive.

He thinks that he should really find a case. A mindblowing one, if possible.

Just then, the phone rings.

Lestrade is already there and he looks foreign too, just like everybody else at the crime scene, but Sherlock only considers it for a brief second. There are more important things to take care of, like- this, now. The thrill of new information, the excitement of something that he hasn't figured out yet, anything (anything that is interesting, obviously). He starts talking and he doesn't really stop, it's always been like that, Sherlock doesn't think they understand exactly how many levels of impossible it is to stop thinking once he's started, to hold back from letting a part of it out because otherwise he would implode on the spot, it's too much thought, putting an ounce of it into words is somewhat cathartic, not to mention that he kind of likes to show off. (wait, cut that out) Everything is clear and when he stops he realizes that he hasn't felt unreal or disconnected since he started thinking-talking. The moment when this dawns upon him is the moment when it all comes back. His vision loses focus for a second, enough to feel a string of panic curling through his veins, making his blood stop for the slightest of a moment. Sherlock is never afraid.

Except that he is, and this is stupid and he shakes it off as fast as it happened. He realizes that he'd been staring into the blank a bit too late, though, because John has already noticed –how much does he?- and his eyes flicker with the faintest of worry, but as far as Sherlock is concerned, John probably thinks that he's just had one of his brilliant moments where everything connects and shines with colour and realisation and everything is fine for him anyway, always, so it's all okay. Perhaps.

John doesn't always know when something is wrong, but he might this time. Sherlock can't tell. It doesn't matter.

It ends with victory and a nasty cut on his forearm. He wouldn't mind it, not usually, but today is different. He feels alive when he's involved in a case- nothing particularly new there, only that now he doesn't feel alive in any other situation. He would have said this before, too, but without meaning it, not truly. He also feels alive when he hurts. It's only natural- smash yourself into a wall and it's guaranteed that you'll feel something. It's not so bad now, just a persisting ache that's almost becoming dull, but it counts as feeling.

Sherlock never indulged in feeling, in emotion, but this was something else- he needed sensory experience. And moreover, he needed to find out what was happening to him. He would borrow John's laptop, after he was done.

'This will hurt,' John warns in his doctor voice, but not with the same worry as the first time when Sherlock got hurt and asked John to fix him, because God knows how many times that happened and it was all a bit usual by now. He didn't quite mind pain, anyway. 'You know, we could have just gone to the hospital this time,' John adds without conviction and Sherlock smiles from the corner of his mouth because it's never a bad time to annoy his friend, but it rapidly turns into a wince of pain- the ethanol stings, but he likes the scent of it, always has. It smells like clean and perfect. He closes his eyes, focuses on the pain; he absorbs it, lets it sink in. It spreads life into him, if only for a few seconds. It feels good.

It could feel better, though. He takes John's hand and presses it onto the wound, dragging it over the cut with just enough pressure. He winces- it feels nauseating and unpleasant and overall pretty bad, because he's focusing on it. It feels alive. The aftermath should be better, though. He once nearly drowned, when he was younger- dazed from cocaine and unstable. thinking of too much at a time, of nothing at all. He'd slipped- as simple as that. It was dark, or at least that's what he remembers. When they'd dragged him out of the river and he'd regained consciousness, he'd never felt so alive in years.

John looks baffled. 'What the hell was that?' His voice is low and he doesn't know how to act. Sherlock hasn't been quite himself today, he understands. John looks at the blood on his fingers, baffled.

'Oh, it'll go off,' Sherlock says and he doesn't know why the sharp outline made its way into his tone, slightly mocking, out of control- he doesn't like people to see him this way, vulnerable, even though he doesn't feel like it, it's just a cut, for God's sake, but it's still something and John is still people. John looks at him and he's clearly worried now.

'Sherlock, tell me what's happening.' He emphasizes on the words, giving them a clear contour, a no-nonsense demand. Sherlock looks at him and he might just be grateful. Perhaps. Only slightly. John is real- there's nothing unsubstantial about him, he's all questions and adrenaline and bad sweaters. Sherlock knows that, his mind knows it, his mind knows everything, but there is a lack of being present in reality that thought can't possibly replace. John is there, but he feels foreign and that is unacceptable because John has been the only one who has never ever felt foreign. Sherlock's not going to lose this now.

He looks at his friend.

'Nothing, I'm fine,' he says for now.

depersonalization, n.: a state in which one's thoughts and feelings seem unreal or not to belong to oneself, or in which one loses all sense of identity

derealization, n.:an alteration in the perception or experience of the external world so that it seems strange or unreal

Well, he should have known, of course, he vaguely remembers it in the DSM, but it was imprecise and it sounded absurd and Sherlock was almost positive he'd never make use of it, so he deleted- misplaced this bit of information in his palace, left it to dust. Apparently, he'd been wrong. He spends the entire day reading everything he can find about it; it's entertaining. It's always comforting to put a label on things, a word that suddenly gives them shape and sense, like piecing a puzzle together. When he's done, though, it's still nothing; this is different from a crime scene. When solving a case, he has to know how it happened more than why. He knows the mechanism of this strange sensation of unreality, now. What he doesn't know is the reason behind it.

It's a bit unexpected, but not really. Sherlock has organized his mind palace in careful areas and shelves and he knows all the pages of all the books in there and not only, but even he couldn't stop them from crumbling down at an earthquake. He hasn't always known this; it's difficult and terrible to understand that his grip on reality is limited. But it is, and he understands now. Or at least he tries to, because the thought still makes the line of his mouth tense in distaste and his brows wrinkle in annoyance and other less concrete parts of him turn in themselves and rebel against it. Genius has more than one curse; the frustration of inevitable defeat is one of them.

Mental stability has never been something that preoccupied Sherlock- it's a limiting concept useful only when establishing if one who committed the crime had been fully conscious at the time or if his psychological state had been altered. He never saw himself in the confines of psychological normality. It's too trite, such a lovely way of simplifying data. After experimenting with all the substances he could get a hold of, he realised that even the human mind is more than its somatic base, it isn't much more. A mental condition that doesn't even make sense won't outsmart him.

(or perhaps it will, specifically because it's so absurd, so out of reach)

He makes sure to bury that intrusive thought in a crack in the marble, safe and sound from ever being rediscovered.

He spends the next few days trying to figure himself out. It's mildly unpleasant, like deconstructing a theory that he's not interested in.

John starts the discussion with characteristic subtlety, while they're eating out on an evening of a perfectly tedious day of living in separate universes in their flat, occasionally intersecting for a glance or a word, or more. It's usually boring, but pleasant, because John is there and he makes for perfect background noise. Today, it was almost unnerving. Nothing feels real.

He puts his hands on the table and purses his lips, not looking at Sherlock and attempting to speak; he does all this exactly when Sherlock expects him to, like a coreography. It's predictable, but it's never dull, even though he likes to pretend otherwise.

`Sherlock,' he starts. `You haven't been quite... quite youself, lately.'

Sherlock takes a deep breath and stops himself from rolling his eyes. `Amazing powers of observation, John.'

John laughs shortly, unamused. `Don't give me this now. Tell me what's wrong.'

And Sherlock tells him. He doesn't know how he kept quiet all this time, he really doesn't, he remembers the fog and the hound, the unyielding fear and lack of logic and how he couldn't function properly for the entire evening, trapped inside a mind that was deceiving him and he'd talked to John then, he had said things that were bit not good and it all passed. It doesn't, now.

`...I perceive myself and reality with the awareness that it all exists, that it's real, but I can't sense it. My body isn't mine and the environment appears two-dimensional. For most people it's a reaction to stress, especially post-traumatic, usually has its roots in childhood events, occasionally it's a prolonged effect of smoking pot. No efficient treatment discovered, though benzodiazepines are reported successful in a decent number of cases.'

John listens carefully as he always does with Sherlock, with an expression of incredulity on his face that's usually an indicator of how fantastic Sherlock is, but now it's more like confusion and bafflement, his eyes widened and his brows slightly furrowed. He doesn't believe it, doesn't believe that Sherlock who is Sherlock and is flawless could feel these feelings that aren't quite feelings, more like amorphous, diffused impressions, alterations. Or perhaps he finds it difficult to believe that Sherlock actually gives them attention. Mental problems are for the weak, John knows that because he had his leg and it was awful and Sherlock just isn't that kind of person.

`I know how it feels,' John says after Sherlock finishes, clearing his throat. `I've been there.` Sherlock raises an eyebrow.

`The war, Sherlock. The sound of bullets and the dead bodies, knowing that I could become one of them in a matter of seconds, that my life was hanging on a thread. I never knew there was a name for it, but I used to distance myself from my body and all around it, I was looking at the whole thing like it was a movie, I was the observer. It helped, a bit.` John, who is amazing, had also felt like this. Why hadn't Sherlock considered it? He should feel more at ease now, but he doesn't, because this is still telling him nothing, even though John also felt it, the fear, the uncertainty, and it was probably worse for him, because John is a good man.

`Fight-or-flight response. Your brain was trying to protect you from all the stimuli in the environment. Successful, apparently,' Sherlock replies and John nods. `You've got rid of it, then.`

`Only lasted while I was scared shitless.`


`I can't imagine why you'd feel like this, though,` John says after a while, confused, his eyes full of that facade of precision that Sherlock loves and of something else, too, something warm that makes Sherlock almost feel human.

`Me neither,' he replies and they aren't pleasant words to say. `Childhood trauma, barely there. Pot, long time ago. Stress disorder, null, it's actually the opposite since I'm mostly bored out of my mind. What can it be?` It's a case, just another case, but the culprit is himself and it's only entertaining when it's not the most annoying thing in the world.

`Maybe you should see a therapist,` John says without conviction, because he already knows the reaction. Sherlock snorts.

`As if any of them could tell me something I already don't know,` he replies. John gives him a look that tells him that he isn't quite spot on this time. He blatantly ignores it.

When John kisses him, it's warm and comfortable and it feels like he's reuniting with himself.

It happens after he's sung one hour's worth of Devil's Trill; he lays his violin down with care, wakes up and realizes that John has been watching him, as he always does, yet Sherlock always discovers the fact as if it was the first time. John's eyes are full of that same warmth that they had in the restaurant, with a hint of adoration that pleases Sherlock to infinity on high. He knows that it's happening in the dilated seconds when he's approaching, it was about time, he feels like he missed John like this even though they've never quite been like this before. John's hand is steady on the nape of his neck as he pulls Sherlock closer, and the ghost of his breath is comfort on his lips.

It feels like home when home still used to feel cozy and safe, like midnight walks through the prairie, like Christmas. He leans in from the first moment, hands resting on both sides of John's neck as they explore each other's mouths patiently, gradually minimizing the distance between their bodies, because they've waited for this long and it hasn't even felt out of place, so there's no reason to rush it just now. It all falls into place like a puzzle that has always been easy to solve, yet beautiful to its core.

`God, you're wonderful,` John whispers against his lips; his eyes are closed, just like Sherlock imagined they would be, with John diving in without any pretense, firm and without hesitation, slow and steady. He is wonderful; they are.

It feels like a crime scene when the distance between them is too much to bear, even though they couldn't be any closer. John's hands are all over Sherlock's body and he can't quite decide where he likes them more; his are on John's waist, steadying himself, keeping them from falling into pieces. It's more than warm now, it's the thrill of exploring and knowing and finding out everything, only that it's not just his mind doing the thinking now, but the whole of him, thrown into the whirlwind, pulled out from the void.

If only for one sharp second, Sherlock feels wonderfully real again.

A/N: Title is a lovely song from Aesthesys.