Firstly, you should understand that, when I answer questions about programming, I do not necessarily think the same things about the word "programming" as do the people you may have heard these claims from, that programming can *only* start when one is a young child.

I do not believe "programming" is the name of a specific, highly-precise process that was genuinely originally invented by abusers who exploited DID and that is *only* practiced in certain ways. The belief that programming can only begin in early childhood is either connected to the assumption that all programmed people have DID (riding off of the fairly true observation that DID does begin in early childhood, but not all cases of programming involve DID), or is connected to how the word "programming" evolved in the past relative to now.

In the past (i.e. 1960s to approximately 1980s), "programming" referred to any kind of cult indoctrination (including people who only joined the cult as an adult). Older sources about "deprogramming", which don't mention things like the alphabet programs, are talking about recovering from cult abuse.

In the 1990s, the word became more associated with conspiracies, because certain conspiracies (such as Cathy O'Brien's claims about Project Monarch) were published that used the word "programming" to refer to a highly specific process that involved Dissociative Identity Disorder. A lot of people who were programmed with alphabet programs (which, as far as I'm aware, originate from O'Brien's claims, at least in the published record) were programmed by people who were effectively copying the content of conspiracies.

I therefore believe that "programming" is best seen as a community term referring to when someone is manipulated using trauma, drugs, hypnosis, or other mental conditioning techniques in such a way where they are conditioned to respond to commands or cues, usually (but not always) associated with switches in a system. I know I've basically said I dislike having to define "programming", but I also know that wasn't the intent of the question you asked, and it just happened to be that, in order to address your question, I had to address the definition of "programming" as best as I could.

With that consideration in mind, yes, I believe it is absolutely possible for someone to be programmed as an adult or a teenager, especially in an organized abuse context like a cult (which, as previously stated, "programming" originally referred to cult indoctrination at any age with any method). It is most likely that some of the programmers my programmer was in contact with were abusing adults, including ones who may not have been programmed in childhood.

As for the question of how *likely* it is for this to happen, it usually depends on whether it is an organized case and, if not, what the abusers would be getting out of it. In addition to the cult example, it is also possible to be trafficked as an adult and have your traffickers program you while you are under their control, which only started when you were an adult.

Programming cases that start when you are an adult and are *not* a part of organized abuse are probably rarer than cases that *are* connected to organized abuse, but they're not impossible. I can't verify this because the evidence would have been on sites that are lost to time, but from how our programmer talked to our internal handlers about the other programmers he was in contact with, it was seemingly accepted by their community that, if you had an adult in your life who trusted you and displayed signs of plurality, you could manipulate them through the methods of programming and effectively program them yourself.

In considering what is possible with regards to this question, it is important to remember that programming does not always result in the victim developing Dissociative Identity Disorder, or even becoming plural. Sometimes, they're ""just"" (heavily in quotes) a person with PTSD or BPD who also responds to certain cues because they were programmed to.

However, some programming is also done on people who are already plural or already have DID. I am under the impression that some of the programmers my programmer was talking to who were abusing adults, those adults had already displayed signs of plurality in some way.

Some people conceptualize programming as "traumatizing somebody into having DID", but this is an oversimplification and does not apply to all cases. If one believes that programming only happens to people who develop DID, or if one believes certain conspiratorial claims about what programming is, it is easy to come away with the impression that it can only happen if the programming begins in the timeframe that DID normally develops in children, but programming and DID have much less to do with each other in reality than a lot of people may think.

If you think of programming as a process of conditioning where the presence of cues and the use of trauma or abuse is more important than the presence of alters or the use of switches, then it becomes easier to understand how programming, or something worthy of being called under the same name, could happen in adulthood.