PTSD - Post-traumatic stress disorder (PTSD) is a type of anxiety disorder. It can occur after you have gone through an extreme emotional trauma that involved the threat of injury or death.
Through 5x02-Impact, 5x05-Unwritten Rule and 5x06-Big Brother, NCIS LA seems to show what PTSD looks like for men returning from action. They hint the most common symptoms that people develop - anxiety, risky behaviour, suicidal acts, Cold hands (Raynaud's syndrome) and stress cardiomyopathy.
For Sam, the emotional trauma he underwent during his torture was relatively easy to recover from. He is a Navy Seal and trained to handle torture and extreme circumstances. Yes, being so close to losing Michelle in the Siderov and Nukes Recovery case in 4x24 and 5x01 episodes, Sam was emotionally under a lot of stress, so much that he lost it with his partner Deeks while on the case. Torture followed him soon later on the mission. And even then, being close to getting killed, the weight that was on his mind was his protective feelings about his wife Michelle who was still on the mission. Sam never actually felt the void emotionally for him to feel the trauma of Siderov's torture. He had his vested interests in the mission and once having saved his wife, he had solid support from his wife and Partner Callen so that he comes to term of feeling the loss that he was almost going to get had it not been for Deeks who saved his life first and then later came on the scene to save Michelle. Like Sam said, he owed to Deeks for the rest of his life for backing him up inspite of him being a jerk with him, while on the mission.
There were a lot of things happening for Sam over his mind while he was under torture. Likewise once out of it he had lot of support from family and friend. He has a worried wife in Michelle and also has a worried partner in Callen to see through his recovery. Michelle doesn't let Sam do his dishes or Callen buys expensive tickets to Laker's game. And personally, Sam is a tough Seal trained to handle and recover. These were the things that let him quickly recover from his trauma. He explains to Nate Getz, his psychologist, one has to "let go", as there is nothing one can do about it. That is the mantra of recovery from the traumatic shocks. And he loves the fact that people care about him. But then it also adds to his anxiety. He is anxious about that day, when he loses it, when he is unable to let it go and he is unable to reconnect to rationality, and what would be the consequences for those who depend on him to protect them. Sam confessed to Nate, that his trauma is beginning to get "cumulative" and his worry is about his ability to "reconnect" like always. He worries about that, but for now decides to push it to the back of the mind and enjoy life without worry, with his loved ones.
For Deeks, the recovery from his emotional trauma is not not so easy. Unlike Sam, Deeks had contrarian situations. He had been singled out in the mission from the rest of the team and was kept on overwatch for Sam. Sam did not want him. Deeks felt himself as the third wheel. If this was not enough, there was an emotional drift between him and his partner Kensi Blye. Amidst solving their issues, in the heat of the moment he kissed her, but they did not have time to discuss what it meant. The emotional drift transformed into the white elephant in the room for them. All of this was taking a toll on Deeks mind with actually none to share his feelings, with nothing to feel proud about and just going about doing his job. May be it was becoming a thankless job. May be he was not the cop that he thought he was, if people cannot trust him. May be doesn't belong to NCIS OSP office and he need not be working anymore with the team, if he cannot be treated as par with them or people have doubts about his character and work style. It is this void, lack of support in the form of friends or colleagues and finally the doubts arising within him about his being suited for the job, which adds to his anxiety post Siderov's torture.
On the physical recovery side, he has new teeth transplanted, slowly recovering to have food from liquid to solid food. However emotional recovery seems distant. Instead he slips into PTSD. He starts worrying about voices in his head and starts wondering whether, he is truly a "Shaggy" like his team calls him, or "schizophrenic" like his partner called him. He starts feeling "halfway being a homeless" as he doesn't feel he belongs to anyplace in particular or anyone whom he can go and feel something with him. He starts feeling the drift. Best understood as it starts when he talks to Sam in the hospital, about "Done being a Cop", when he talks to Kensi in the Bullpen at OSP about what he plans to do "I don't know", when he talks to Hetty at his home about him having a case of "Insomnia" and when finally talking to Nate, the OSP Psychologist; about what worries him and why he is unable to sleep. He is worried why his mind won't stop running and what happens if it does not stop. Nate explains that its a positive sign indeed for him to worry about it and that does mean that he is on the right path.
It is also amply clear to Nate that Deeks doesn't have any support system that he can fall back on like Sam could. There is no one at Deeks home or in his mind a friend who can take care of him or if he could talk to. This causes his concsious mind to concentrate on his worries rather than sleeping and having his subconscious resolve the worry for him by adding a meaning to the torture and trauma he underwent. Nate tries to help Deeks, by providing a possible support in his partner Kensi Blye. As a psychologist, Nate cannot suggest anything, but he just adds that reference so that Deeks can start thinking about something else than his worries. Indeed the thought of Kensi is much more warmer and meaningful than him trying to find an answer to his anxieties in a fast track manner. However, as it seems wonderful, its not that easy to just talk to Kensi, especially now that he kissed her and doesn't know what to do next. Kensi never raised it again. He doesn't know whether she approves it or disapproves it. So what happens next? Ball is in Kensi's court.
Readers can read my other analysis I wrote about the Impact on Deeks that caused a greater trauma to resolve. "The Understated Action and Psychological Drift through Season 4 Ending to Season 5 Cold Opening"
Like Nate and Hetty rightly observe for people dealing with their PTSD, they need to have support systems in place. Hetty starts it with a carrot and stick approach. She makes a visit to Deeks apartment and expresses to him that she needs him to report back to duty, if he does not want her to start looking for a replacement for Kensi for a new partner. It works indeed. All of a sudden Deeks feels "wanted". He means something to his Manager and so she took the trouble of visiting him at his home. Now he has to see if Kensi feels him wanted as much at workplace. But that thought only opens up the can of worms in his mind. Kensi has been calling him. Repeatedly and he has been declining her calls. Why? Why is unable to talk to her? What has changed? He doesn't know if she is calling him with the sympathy she has for her partner or she actually cares about him. She definitely cares about him. But that care is only for him as her work-partner. Whereas He, loves her. What if she doesn't feel the same about him. He cannot resolve truly, what he has with Kensi for a relationship, just the partnership or something he longs for more from her. Kensi doesn't provide him any hint. It keeps on adding anxiety to his already anxious mind yet to recover from the emotional trauma. Wish he could just sleep! so that he could go back to work and see how matters stand right now with Kensi !
Amazingly, Kensi lands at his doorstep, with dinner in her hand. She wants to avenge Deeks ignoring her Cronuts that she put at his doorstep. She wants him to have dinner with her and also watch a boring movie "Burnt Offering". After all Kensi doesn't just want him as her work partner. She wants him to watch along with her, the bore movies that she loves. She loves them indeed, but cannot watch them alone. She is now wanting to watch one with him. Ofcourse, it may not have been direct saying by Kensi that she loves him. But when has been Kensi been direct with him or said more than what she wanted to say. Kensi does love him. Its a Love Story indeed between him and Kensi. That is how he is able to answer the question that Nate posted about his relationship with Kensi.
A visit from Hetty, Nate and Kensi suddenly makes Deeks feel at home, come away from drifting into being homeless. He sleeps. Insomnia getting recovered. That was in 5x02 Impact. Pretty soon from thereon, Deeks starts on his healing journey. The slow journey of Deeks recuperating from his PTSD and his anxiety issues starts through his reactionary approach to interactions around him. The ice-breaking moment is of course him rejoining the team in 5x03-Omni. Hetty gifts him with a new gun but having same safety manual. That's how much well his boss knows him. So does Kensi know his personal preferences about his gun. What else can he want? Two of his dearly loved women taking care of him now. But is he ready for work? Can he shoot? That's his anxiety. Hetty's note to not close the box, forces him to test himself at the firing range. Kensi's questions if he is back to work, forces him to accept that yes, he is back to work, but one day at a time. After a day of work with hits (diving down to save a woman's life) and misses (failing to gun down a man), Callen states to him, that he cannot accept him back to work if he keeps second-guessing himself. That forces Deeks to look into Callen's eyes and say that he is ready for work.
Deeks anxiety is now centered on Kensi. Kensi had mentioned to him “how she missed him at work". Kensi’s words and actions matter to him. She missed him, then he makes sure that he comes to work regularly. She is worried about him not taking a shot or trying too hard to make him a competitive Agent. Yes, he indulged in wall climbing competition with Callen to make her happy in 5x04 episode. He never ever did that before.He is bent on proving to her and everyone that he is doing good, ready to take any kind of risky job. If she thinks he is trying to kill himself by riding a motor bicycle like in 5x05 episode, because statistics speak so about a PTSD patient, then he wants to prove her otherwise that he is taking care of his health by doing exercise that is good for his heart through a treadmill installed at his work station in 5x06 episode. All of this is going quite overboard with his antics to address Kensi's concerns and make her go away from baby-sitting him. Her answer to his saying that "she does not have to worry about him" is that she does have to worry about him as he is her partner. It is good to hear that but it is certainly not pleasing for Deeks to get saved by Kensi like it happens in 5x05. This is now certainly directing him to address his anxiety around his "emotional center" like Hetty warns. His emotional center is Kensi and Kensi is certainly more worried about him than she should be. He needs to quieten down for her sake, so she can calm down. Further, he needs to focus and get his emotional control back. He needs to get away from doing what Kensi does, bike rides, competitions etc and instead do what is pleasing to him.
He has to take support from Hetty to find himself back. Without Hetty's support and guidance, Deeks would not have known what he has to do. Those four episodes from Impact to Livelong Day, all have Hetty's push for Deeks to get better. His treadmill idea is not taken seriously and seen as an antic by everyone in 5x06, but Deeks sees it as non-risky diversion for him away from Kensi and infact a good exercise to stabilize his emotions. However, he realizes how bored he is trying it too hard to make any point. He starts letting it go, starts relaxing in his natural way. He is back to taking caffiene, coffee like he does normally. That is the 5x06-Big Brother Stakeout moment in the car, where without his realizing, he starts teasing Kensi like his old self. He is picqued that she doesn't like a moustache and here he is with all that bearded face. He teases her about her dislike for facial hair. Its a small gesture though, but definitely the indolent, easy going, drawling Deeks is back.
The next episode 5x07-Livelong Day has him finding fun by himself reading about planetary movements, studying Astrology. Mercury in retrogade is fun, but more importantly the case closes with Deeks not only enjoying his undercover Ops with Kensi in a very comfortable way, it closes with Deeks getting the Prairie Tac train to play that he had yearned as a child since he was five. To me that was the moment, when it felt to me that Deeks was cured of his PTSD. His childlike innocence, sparkle, imagination and twinkle in his eye takes him away from all cares and just lets him into his native Deeks state, which he was so worried of losing as expressed when talking to his psychologist Nate Getz. Probably that moment on everything starts making sense. It is also the episode where Deeks plays the undercover part of FRA employee Matthew who suffers from OCD and has anxiety issues on a simple case as Fire alarm ringing. Deeks in clear contrast is far recovered from PTSD issues. He is now playing with those symptoms to work on his undercover role. It is also the episode where Hetty instead of indulging his wishes or chastising him, just teases him with pleasure about his Mercury retrogade talk and also shares his excitement about the old train, though in excitement she does ruin his effort about building the track for the train and spoiling the fun for him. She is confident about Deeks in every way that he was recovered and it was also an excitement within her with the same feelings as Deeks for the train. That settles the matters for everyone including Deeks, that his antics or eccentricities can be fun and emotional for others too. No more anxiety issues and no more Deeks antics in Bullpen to make a point.