Yes, this review has been a bitch to write.  After all, so much was packed into this mere 42 minutes.  When "The Born-Again Identity" finished at 9:58 on Friday evening, I do admit to being shell shocked.  Oh sure, I loved the episode, but my mind since then has been trying to process so many things.  The problem is when you've been reviewing this show in depth as long as I have, your brain instantly tries to connect the dots.  There were a lot of dots.  
I had to watch again.  And again.  Now with six viewings in, I still don't think I have a full grasp of it.  Not that this is a bad thing.  Not at all.  The episodes that I always remember are the ones that leave me thinking.  
Since the episode has aired, I've been reading a lot of comments on this site and others.  Some are disappointed and I do get why.  The issue of is one of expectation.  With fans, they were high.  After all, the writers set that up by not addressing two elephants in the room for fifteen episodes and then choosing to play out both of them at once.  I'm sure several fans were hoping for more than a quick 42 minute resolution. 

All isn't resolved of course.  Castiel's story certainly isn't done.  Misha will be back for at least two more episodes this season (and no one is saying which ones).  Sam's situation may not be totally fixed either, but at least he's doing better.  Before I dig too much into the analysis though, let me get the criticisms out of the way.  There aren't many.

I have one major criticism with "The Born-Again Identity."  I've often called it "Short Attention Span Theater."  There's been a lot of filler this season.  Most of it has been good filler (along with a few stinkers) but they still haven't been addressing the core issues like Sam's psychosis, the Leviathan (short of Dean's weekly phone calls to Frank), and what happened to Castiel and Bobby.  They've been showing MOTW stories.  While I like MOTW stories, I really don't like that when they do decide to visit the season's mytharc, they try to cram "everything plus the kitchen sink" into one episode.  What played out here could have easily been done in another episode.  They did the Leviathan last week (good), so why not Sam's breakdown this week and Castiel's return next week?  After all, there are 23 episodes this season.  There's room to break it out. 

Because of the two very intense and involved stories in this episode, which both individually were amazing, often the back and forth was jagged and lacking fluidity.  I'm sorry, but it's a tall order in anyone's script, let alone Sera Gamble's, to blend a demon action drama with a man slowly falling apart in a mental institution.  The two really don't mesh without impacting the emotional elements of the stories.  I did this exercise, I watched on my iTunes download all the Sam scenes together and all the Dean/Castiel scenes together.  Suddenly, I got far more emotional impact out of the stories.  They are really great individually.   

Out of the entire episode, I was most dissatisfied with the ending.  Not what happened, I think that was brilliant, but it was so rushed!  Because of the crowded script, there wasn't a lot of room for many emotional moments.  There were two that got me hard, Sam and Dean's talk in the beginning and me watching Dean give Castiel his trench coat back through a pool of tears, but there was room for more.  For example, at the end Sam had slipped into a catatonic state.  He couldn't even communicate anymore and never got to tell Dean goodbye.  Was it wrong of me to hope for an emotional Dean scene at Sam's bedside before Castiel came up with his solution?  And what about Sam's frustration at the end over leaving Castiel there?  It was over in less than a minute.  He said his protest, Dean made his argument and they left.  This really could have played out better.   
Those are the only issues I had though.  I think the writing we did get was brilliant and the acting was top notch.  I was at Salute To Supernatural in Nashville when they were in the middle of filming this episode.  Jared showed up in one hot looking beard and judging by his comments, I got the impression this episode was stressing him out a little.  Playing crazy Sam was really stretching him.  If he was concerned, it didn't show one bit in his performance.  I really can't come up with the ideal set of words to say how incredible Jared's portrayal of a broken and pushed to the brink Sam was.  
Sam's Story
Poor Sam has always taken what's been dished out at him and tried to soldier on.  In this episode, it took every single bit of his energy to fight off Lucifer, and he slowly lost ground each time.  He softly crumbled, which is exactly what I would expect with Sam's character.  As much as I really love Castiel and I am so thrilled to see him back, I was most looking forward to Sam's breakdown playing out.  It was a long time coming.  We all suspected Sam wasn't right, and it was inevitable that something would happen to make him crack.  I found it to be quite clever that is was nothing earth shattering.  Just a simple listening to the devil to help solve a case.  That one tiny "shut up" cascaded into extreme psychosis and near death.  Just wow.  Sam never stood a chance.    

No scene frightened me more than the beginning scene, when Sam ran through seedy back alleys in a fragile mental state alone, falling apart in front of the "tweaker."  We've seen Sam at tremendous lows, "When The Levee Breaks" comes to mind, but this is the lowest he's ever been.  He's in a dark alley seeking drugs to help his problem.  This guy has never allowed himself to touch more than an aspirin.  It's scary and when it doesn't work, I'm just as freaked out as Sam.  That well choreographed and out of nowhere car accident made me jump!
I like the notion that Sam is ready to give up and die.  That line "I'm too tired" had so much hidden meaning behind it.  He isn't just talking about his current bout of fatigue.  He's talking about the endless barrage of misfortune and fighting to save a world that's determined to doom itself one way or another.  He's had too much loss, too much pain.  Given his current state, he just doesn't have the strength anymore to do this just for Dean.  He's reached his limit.  He doesn't want Dean to put himself through the pain of trying to save him either.  Dean has been through enough.  

Sam only has one option left, riding out the extreme torture in his mind, slowly deteriorating with each passing hour.  He's chilled when reminded that he's in a locked ward alone with Lucifer, just like when they were in the cage.  He can't eat, since his hallucinations are putting maggots in his food.  He doesn't even have the physical strength to open a candy bar wrapper.  He's jumpy and nervous every time Lucifer makes a noise.   He becomes more terrified and frozen with panic every time Lucifer appears.  His only saving grace is his interaction with another patient, Marin.  

I wasn't sure about the story with Marin at first, but she did give Sam a purpose that made me smile.  Sam is at his best when he's helping people. Honestly, if Sam didn't have that distraction, he would have spent the entire hour lying in bed depressed and waiting for the end.  Notice how Lucifer wasn't around in some of those moments with her?  Sure at first Lucifer drowns her out with a bullhorn, but it isn't until they make the salt ring that Lucifer breaches their time together.  It gave Sam purpose and showed us one of the most appealing things about his character.  No matter how bad things are for him, it doesn't prevent him from helping someone else.  It's that ingrained in his nature.  He isn't doing this for his well being.
I love the scene where Sam and Marin put her ghost brother to rest.  Sam is so bad at this point that he can't even put down the salt circle because Lucifer's mere presence is debilitating him.  The terror in him now is very raw and there's not much left of his psyche. He's able to pull it together enough though to get into the circle and burn the bracelet.  The ghost causes some destruction but Sam's willing to take the fall for it.  Marin leaves just in time while Sam is restrained.  This again is another example of Sam's noble character, he tries to do the right thing no matter what the consequences.   

Sadly, after this point, reality escapes Sam.  He can't concentrate when the doctor tells him about surgical options.  Yes, I did actually yelp over seeing that clump of Sam hair on the pillow.  Not the hair!  The rotting fingernails I could take but not the hair.  

Sam's barely lucid when taken by the demon into electro-shock.  I did love how the electro-shock scene tied back to his earlier hallucination of the doctor telling him he would experience a whole new "ten."  I do wonder if the electro-shock is actually what pushes him over the edge.  That must have been his ten.  From this point on, Sam is locked in his mind.  All he sees is Lucifer and he can't even process that his own brother and a long lost friend are in the same room.    
Dean's Story
Poor Dean.  He's really raw at this point himself.  When it comes to Sam though, he won't give up.  Sam still remains his only reason for carrying on.  

It's on the playback that I realized how heart crushing Dean's conversation with the doctor was.  Dean barges in angry that he can't see Sam, and when the reason is given, Sam has been admitted to the locked psychiatric ward, Dean's anger instantly shifts to shock and concern.  He knew things were bad with Sam, but he didn't realize this was another full blown psychotic episode.  He tries to defend, claiming Sam isn't the Norman Bates type psycho, but he can't argue that Sam is okay.  I'm especially touched  when the doctor questions whether the insomnia caused the psychosis or the psychosis caused the insomnia (yes).  Dean answers that question when he says the sleep thing is something new.  The doctor's "right" says it all.  This isn't Sam's first psychotic break.  
I tried to picture what was going through Dean's mind when making those calls in the cabin.  What he's doing is definitely a desperate act, but I couldn't help but remember his conversation with Bobby in "Meet The New Boss."  He's always suspected that Sam's mental issues can't be fixed.  It wasn't until he saw Emmanuel though that he entertained the possibility of the wall being put back up.  It's the one big hope he rode on.  He even blamed Sam's condition on Castiel taking down the wall, when in fact the origins can be traced to Sam's time in Hell.  

This ties into what Sam tried to tell Dean.  The wall was always a risk and what's happening is inevitable.  A soul gets damaged when put in Lucifer's dog bowl, no matter what.  Sam's broken psyche would always be there, ready to surface at any moment like it did in "Unforgiven."  Was rebuilding the wall really the best thing for Sam at this point?  I don't think Dean asked himself those questions, and I don't blame him.  The circumstances are different here.  The alternative now is no longer insanity.  It's death.  Desperate times.  
Dean's partnership with Meg is very interesting, but not out of line.  It's no different than him dealing with Crowley at the end of season five.  He had no choice but to work with her.  He won't allow Meg to tell Emmanuel who he is, even though Meg is right that having the power of a full blown angel would be better.  Only one thing matters to Dean, Sam is dying.  With that kind of desperation, even working with a demon becomes acceptable.  It's again another example of the lengths these brothers will go to protect one another.  
Dean even for Sam's sake put aside all that lingering resentment toward Castiel.  Healing Sam is all that matters.  Once Castiel remembers all the horrible things he had done, including breaking Sam's wall, and wants to leave, Dean talks him through it.  "We didn't part as friends, Dean."  "So what?" Dean answers.  He even shows Castiel that he kept the trench coat.  Dean may have been hurt, but he never forgot his friend Cass.  Apparently that counts for something.  It counts for everything.  

I do also believe that Dean is able to let go of that resentment because of his final line to Sam at the end of the episode.  "We don't have any friends.  They're all dead."  That is a perspective changer, isn't it?  Dean really has come a long way.  
Emmanuel/Castiel's Story
I did feel really bad for Emmanuel/Castiel.  To think, this whole time he's had no memory but living in bliss.  Something in his mind probably didn't want to remember.  He felt blessed, he had a wife, he was healing and doing good in the world.  As usual though, all it takes a twist of fate to bring him and Dean together, if you want to call these strange ghost like phenomenon that's been happening to Dean fate.  I still say it's Ghost!Bobby, but that remains a mystery.  
My absolute favorite scene of the episode is when Castiel goes to smite all those demons guarding the hospital.  He's just been told he's an angel and has the power to do it.  I like how they played the awkward angel humor here.  Castiel doesn't remember how to smite.  "It's in there.  I'm sure it's like riding a bike," Dean tells him.  "I don't know how to do that either," Cass replies.  Cue the patented and most hilarious Dean Winchester eye roll.  Oh, how I missed these little nuggets.  Welcome back Cass.  I also love how Dean is nervous, but Meg's optimism is priceless.  "I believe in the little tree topper."  

What happens is epic.  Cass smites, and with each golden glow of his victims the memories rush back.  His first encounter with Dean in the barn.  His defiance against  Zachariah and rescuing Dean.  Breaking Sam's wall.  His partnership with Crowley and putting back the souls in purgatory.  Dean watches the whole thing stunned, Meg is smiling.  "That's my boy."  She even brings back her old nickname for him.  "That was beautiful Clarence."  It was indeed beautiful.    
Unfortunately, there isn't enough time for Castiel's story to play out much.  In forgetting who he was and becoming a healer, he had to have been returned for the purpose of redemption.  Dean nailed it when Castiel wondered why he emerged from that river.  It's too late to fix things.  "Maybe to fix it," Dean says.  The best way to change the world is one person at a time.  Out of all his crimes, his betrayal of his close friend's brother was his worst.  Sadly, by the time he gets to Sam, apologizes, and tries to make things right, it's too late.  The pieces of the wall have crumbled to dust.  Sam cannot be healed.     

The Ending
I've watched the final three scenes more than any of them, if anything looking for clues for next time.  They obviously left some things to be resolved.    
To be honest, I especially was taken by Dean standing in the corner, looking very despondent to see Sam in his catatonic state.  As I said before, I was hoping for more there.  That is after I stopped chuckling over Lucifer reading "The Three Little Pigs" to a nearly vegetative Sam and trying to explain it to him.  I haven't in this review yet raved about how amazing Mark Pellegrino was in this episode.  Sure he is funny most of the time, but he's really scary too.  It's because of him that I was purely petrified for Sam.  Lucifer gloated in his victory over breaking Sam, that's for sure.  "It's hard to believe you were the guy that saved the world once."  

Going back to Dean though, his answer to a very remorseful Castiel really crushed my heart.  "So you're saying there's nothing?  He's going to be like this until his candle burns out?"  Then Castiel comes up with the shifting idea.  He even assures Dean he will be alright.  Being an angel, he won't die from exhaustion, that's for sure.  It's a horrible burden, but it's the least he can do in making things right.    
From a VFX perspective the whole shifting thing is really cool, but it killed what slim emotional impact I felt from this scene.   Even when Sam came out of it recognizing Dean and asking "Cass, is that you?", little time is given to Castiel's newly altered mental state and Sam and Dean's reunion.  
For those of you that wonder, I'll fill in the blanks as to what happens next.  Orderlies and a nurse take Castiel away for examination and admission, Dean and Sam look at one another, then Sam yawns and rolls over.  It's time for bed!  A day later, they leave.  I'm hoping that in the beginning of the next episode, Sam wakes up from his week long nap.  He still looked really tired in the next scene with Dean by the car, which BTW is a 1968 Dodge Charger 440.  The ugly front grill gives it away!  

Seriously though, what we saw in that insane asylum was likely how far Sam's soul was pushed in the cage.  Almost destroyed.  Death even said in "Appointment in Samarra" that Sam's soul was frayed to the last raw nerve.  I picture Sam's last moments in Hell to mirror that last scene in the hospital before Castiel touched him.  Broken, only seeing the torment of Lucifer.  That certainly matches the hopeless and despondent Hell Sam we saw in "The Man Who Knew Too Much."  
What does this mean for Sam now?  His psychosis is fixed, but the memories of all that torture from Lucifer, both in Hell and on Earth, are still very real.  It'll probably continue to haunt him for a lifetime, much like Dean's experiences in Hell.  I doubt a lot of time will be spent on the screen anymore showing this pain though.  He'll continue to do what he always does, solider on until he dies.  It's all he knows.  That applies to Dean as well.  
Do we call this then "a quick fix?"  Perhaps, although quite frankly Sam really has suffered enough.  It's about time he caught a break.  It isn't just Sam's break, it's a sorely needed one for Dean as well.  Maybe they can finally get on with worrying about themselves individually and not each other like Bobby had hoped.  There's a story line I wouldn't mind seeing.  Both Winchesters rebuilding from their entire ordeal since "Swan Song" instead of just reacting.  

Castiel's torment continues though.  He may have redeemed himself in the Winchester's eyes, but he still owes the world.  He did after all let the Leviathan loose.  There's plenty more of Castiel's story to tell, and thankfully, Misha is open for season eight.  I'm hoping Sam and Dean remember their friendship and come back to save him.  After all, Sam was right, they can't leave their friends behind.  
For the record, I adore the idea of Meg being at the mental hospital watching out for Castiel.  While I know that Meg's motives are clearly self centered and she's interested just in his power, I do think she likes Castiel.  All you have to do is watch their scenes together in "Abandon All Hope" and "Caged Heat" to tell that.  I'm still hoping for angel on demon action, but it's obviously not the time is not right now.  Their's truly is a strange pairing, isn't it?  I like the idea of creatures from Heaven and Hell battling together to fight the Leviathan.         
Overall, I shift back and forth between giving "The Born-Again Identity" an A- or B+.  It would easily be in the A range if it had more emotional punch and the end wasn't so rushed.  No matter, it was still a very good episode.  I like several of you though had hoped for a little more.  Ah well, there is an entire rest of the season and beyond for that.