A crazy theory appeared around me after seeing few oddities in the manga/anime:
Shinichi would be fallen into coma due to Apotoxine after his first meeting with Gin and Vodka.
I developped this theory after reading an other theory about Ash (pokemon) would be fallen into coma after spearow incindent and explain why he not aging, or all nurse joy and officer jenny are indentical. See ash's coma theory
I have noticed, that most of explanitions used in "ash comatose theory" can be applied for detective conan universe.
All adventures that Shinichi has lived since start of serie are not real, and only due to his dreams.
In fact, he is falling into coma after had been poisoned by Apotoxine, after his encounter with Gin and Vodka at Tropical Land. And to survive, his subconscious created an idealised world for him, where he could be use his skill to achieve his dream: "become the most skilled detective in the world", and find a mean to out of coma.
In world of Conan, nobody aged despites the years passed, because Shinichi fall into coma; his life is on standby and his subconscious apply that in stopping growth for all people appearing in Shinichi dream.
We notice, that most of recuring characters appearing in this manga, has been encountered by Shinichi during his past (vermouth, akai, etc). His subconscious doing that, because it's easier using already seen people for relatives.
Otherwise, they look like him or relatives: Kaito and Aoko, Heiji and Kazuha look like Shinichi and Ran (physically and behaviorally). An other mean to his brain, to create characters.
Shinichi, finishing to solve all of the cases, because it's created by himself, and few time, a déjà-vu appear due to a bug (north star case with yusaku novel).
The moments where Kudo recover his real body are attempts from doctors in real world to heal him.
Few characters portray a part of shinichi personality and means to maintain the world.
-Conan (hi current form) portray a barrier, notably to have relationship with Ran or resume a normal life, and a little protect from the death. Recovering his body, is one of purpose solving to out of coma.
-Agasa portray the science evolution: most of technologies seen in the serie result of inventions built by Agasa that Shinichi saw before his coma, and logic (mobile phones, computers, become more powerful, multifunctional, etc).
-Ai haibara portray the real world, a means to help Kudo out of coma by solving black organisation and Apotoxine mystery.
-Kaito Kid portray his opposite personality: a genius using skill to commit crimes, but he don't kill because he is a personality of Kudo.
-Detective boys portrays a security valve, a mean of relaxation to decompress and avoid brain stress.
-Black organization (and child size) portray his coma. Destroy Black organization and recover his body is the goal that Shinichi brain created as riddle to save him with less danger for his body.
What do you think about this theory?
Have you other example to complete this?
PS: sorry if there are mistakes (i'am not English).