[Spoiler Warning: This post contains information pertaining to Deadpool and various other media related to Deadpool.]
So, I saw Deadpool the day after it came out in North America and I have to say, it was phenomenal. However, as a fan of the character, I felt that it was missing a rather important part of Deadpool's personality: his other personalities. They covered the other main attributes - dark humor, inability to take anything seriously, fourth wall breaking. Yet, there was not one voice-over from another part of Deadpool's mind. I've read several articles pertaining to what can be done in the sequels, though not a single one mentions the voices in his head. I understand that some people would argue this wouldn't work, but I'm proposing how it could work and why it has worked in the past.
The Psychology of Deadpool's Schizophrenia:
So, it's a common trope to view one's morality in any difficult situation as an angel and demon sitting on your shoulders. With Deadpool, it's more of a Freudian explanation: Deadpool is the Ego and his voices are the ID (yellow text boxes) and Superego (white text boxes). Deadpool's ID always has more of an excited tone of voice and fits more with Deadpool's antics such that he usually listens to what he says as opposed to his Superego. The Superego is more calm and attempts to push Deadpool towards a more civil mentality . . . which is a serious exercise in futility.
While it is never actually explained how these voices came to exist (at least not that I know of), I'd venture to say that they came about in response to the insane level of Hell Wade Wilson went through from training with the Canadian Special Forces to the torturous treatment under the Weapon X program. Instead of developing PTSD, Wilson developed a carefree attitude and something of an invincibility complex (what with the healing factor and all). However, some sane part of his brain continually attempts to keep him on a moral path which lead to a fracturing of his consciousness. Obviously this explanation is rather lengthy for the movie, so it'd probably just be best if the Superego and ID attempt to explain themselves to the audience on their own, but more on that later.
Examples from the Comics:
Deadpool's schizophrenia, much like the Joker's origin story, is cannon depending on which writer is at the helm. Some Deadpool comics have the voices present whereas others (ie Cable and Deadpool) do not. However, I can provide a few samples from the comics where they were present including the cover photo:
In my favorite Deadpool run, Deadpool Kills the Marvel Universe (and its subsequent series, Killustrated and Deadpool Kills Deadpool), the voices in Deadpool's head are brought to the forefront to best explain how they control his actions. The basis for the original series is that Deadpool is taken to a mental hospital by Wolverine because he and the X-Men are sick of dealing with him. The "psychiatrist" is actually a supervillain attempting to create an army of mind controlled villains much like Iron Man did in Civil War. This plan fails due to the fractured mind of Deadpool and leads to the creation of a NEW voice:
This new voice then obliterates the fourth wall by explaining to Deadpool that everyone he has ever known and loved (or maybe hated in some cases) is doomed to live the stories carried out by the writers. Thus, he should kill them to end their suffering. This new voice is so convincing that Deadpool commits the bloodiest rampage ever to grace the pages of his comic.
To me, this alone is a testament to just how pivotal Deadpool's schizophrenia is as a character trait. Obviously this story can't be played out given the movie rights ordeal, but I'd like to commend Benjamin Allen for at least suggesting it as a possible sequel.
How It Could Work in a Movie:
Again, the counterarguments here are that it would be hard for the audience to grasp Deadpool's voices along with the attempt to explain what they are to the audience. I suggested that the voices simply do their best to explain themselves - most likely talking over each other as is the chemistry they typically have. However, it's also important to look to the Deadpool video game wherein the voices added their banter to the chaotic events of the story. The most notable scene, in my opinion, being their combination of reality and comic book formatting:
In a similar manner, Deadpool could easily grab a text box or two and use them as weapons to fight off his enemies. Or, he could just simply fight with himself to add to the usual banter of the comics. If they really spun it right, they could go so far as to show what such a scene looks like from the perspective of other characters (a la Cable). This would allow them to maintain the low budget without having to spill over on CGI and coordinating the use of text boxes. Instead, it could just be Deadpool using different tones of voice to argue with himself whilst Cable looks on confused and vexed as ever.
Honestly, I'm just really interested in seeing Deadpool's other voices make it into the movie. I'll leave the execution of this to the producers and director, but if you have any suggestions, as established in my previous post, I'll happily credit you for plausible ideas!