A/N: I do not own Sherlock, obviously. Also, please feel free to review, as I enjoy constructive criticism and shameless ego-stroking. As a side note, I'm taking requests for future 'misdiagnoses'.

1. Anorexia Nervosa

"Sherlock." A pause, then a second attempt. "Sherlock."

An annoyed growl. "What." Not a question, not even really a response; a statement. A testament to how disruptive the calling of his name was to his concentration.

"Sherlock." Pure patience.

"What!" Finally, the detective turned away from the microscope to look at his flatmate, who was calmly – irritatingly – calling his name over and over from the armchair less than ten feet away. "What!" he repeated, when John did not answer quickly enough.

John said nothing further, only glanced meaningfully at the bowl of pasta sitting at Sherlock's elbow, untouched.

The world's only consulting detective took one look at the bowl, and immediately deleted John's concern. "I'm working," he snapped testily.

"It's probably cold by now…"

"All the more reason not to eat it."

"It's been five days."

"Incorrect." This was not the first time Sherlock had lied, or misrepresented the facts, when it came to his eating habits.

And John was getting worried. Legitimately worried, enough so that he was starting to draw a rather terrifying conclusion.

For the duration of the current case, John observed his friend carefully. He started looking for 'the rules'. In most cases of disordered eating, there are rules and guidelines by which the patient conducts their eating habits. Many times, it has to do with a certain number of calories consumed, forbidden foods, or times and places when eating is strictly prohibited. Sometimes it is even necessary to keep from eating in front of certain people, or outside of the house at all. And so John Watson watched. He discovered, unsurprisingly, that Sherlock had his own set of rules.

First – he did not eat anything that had fallen onto the floor. Ever. No exceptions. Even if it was still in a wrapper or container.

Second – he did not eat anything that was not expressly his. If John offered him half of his sandwich out of sympathy when Sherlock's own meal had gone cold, he refused it unwaveringly. Common items in the kitchen such as a box of doughnuts, or some tartlets that Mrs. Hudson brought up, seemed to be forbidden.

Third – toast seemed to be a go-to. That, and tea. These two things Sherlock subsisted upon when he was working, and even then, only as necessary.

Fourth – coffee was exempt. This he consumed with alacrity and abandon. Very curious.

Fifth – talking about eating, being asked to eat, being presented with food, or being harassed in any way regarding his eating habits, seemed to make him tense and irritable for several hours at a time.

"Sherlock?"

"Mm. John."

Thinking Time. Better to interrupt Sherlock during Thinking Time than Microscope Time. And as Sherlock was now lying on the couch with two nicotine patches on his arm, his hands folded in the prayer pose, eyes closed – it was clearly Thinking Time. John dared interrupt him. Sherlock did not deign to open even one eye. The doctor pressed on anyway.

"It's been a week."

Sherlock seemed to know what this was about straightaway. "Had toast this morning."

"And?"

"Tea."

John sighed.

"Digestion slows me down. We've covered this."

Indeed. John gave up and trudged off to bed.

The next morning, John rolled out of bed painfully. He'd slept poorly the night before, having gone to bed dissatisfied and anxious, and was now being rewarded with a sleep-deprivation headache and a crick in his neck. This, he decided, was reason enough to be finally, absolutely done with Sherlock's antics. If he had to strap him down and put a feeding tube down his throat, that man was going to face up to his problem and eat something. And then get checked into rehab.

These thoughts burned in John's mind as he descended the stairs, fists clenched at his sides as he braced himself for the fight that was about to ensue. He was already composing a speech in his head when his feet hit the bottom landing. "Sherlock, this is it, this is the last straw, you and I are going to sit down and –"

He stopped midsentence, and nearly fell over, as he caught sight of Sherlock.

Sitting at the table.

Surrounded by a plethora of messy dishes.

Halfway through a(nother) cheese Danish.

Binge?

Misdiagnosis?

John reeled.

"Good morning!" Sherlock chimed as he finally noticed his flatmate swaying at the bottom of the stairs. He was obviously taking a great deal of pleasure from seeing his friend so taken aback. "Started without you. Famished. Eggs?"

"What…" The doctor scratched at his head, not sure whether to be relieved or twice as worried as he'd been before. "Digestion slows you down…?" he floundered.

"Correct. Case is closed. Solved it last night. The sister did it. Unexpected, no? Fried, scrambled, or poached? I made all three."

"But…"

"Yes, yes, I know what you thought, and you thought wrong. I couldn't very well go on being me if I were to do something self-destructive like starve. On purpose." He shook his head. He wasn't keen on explaining himself most of the time, but now with the case out of the way and with John looking like he was ready to faint, well… No harm in it. Just this once. "I also know what you're thinking now, and I can tell you that it is also wrong. Do you remember what I told you before, about seeing and observing?"

"Yes…"

"Well, there is such a thing as 'observing' too much. And that is called imagining."

DISCLAIMER. If you ever suspect that anyone close to you has an eating disorder, seek professional help immediately. We all know that everything is well with the World's Only Consulting Detective, but you can't always be so sure in real life. Safe is better than sorry.