There are far too many terms for medical conditions. Moreover, while these terms are convenient ways to reference a package of possible symptoms and difficulties when talking with medical professionals, very few people outside of the medical profession have any idea what the terms means or how the condition is supposed to affect what someone is supposed to do when in the presence of someone with that condition.
Thus, instead of seeking to create a specialized term that few will understand because there is no common Mando'a expansion, culture, or major group that most people look to for information, stick to using words that exist in core Mando'a to describe symptoms and needs. Make your priority imparting information that is actually useful for getting your needs met. If you really think it would be helpful to your audience to know the medical term, rely on a mutual Earth language for such words, using Earth words (or Basic, if you're writing a Star Wars story) as temporary loanwords.
Some expansions of Mando'a use mir'shupur as inspiration to create two broad categories of personal challenges: mir'shupur (brain injury) has been expanded to cover all mental illnesses and challenges (including social ones), and baar'shupur (body injury) was created to cover long-term physical injuries and ailments (including hidden ones). In either case, the appropriate term indicates that a person needs extra patience or assistance because of a mental or physical challenge that's not immediately obvious.
In English, a language with millions of words, people with various mental, physical, and social challenges are still trying to come up with precise words to describe everything they are experiencing. If an Earth language with a long history and a full culture behind it can't do it, why should we expect more out of one based on scraps from fiction?
When people go into servers or post questions about a word for this or that physical, mental, or social challenge, what people actually are asking for is a symbol that can be recognized "among the greater Earth Mandalorian community." To be perfectly clear: there is NO "greater Earth Mandalorian community." None. There are different pockets of Mandalorians on Earth, and a few of them have even met in real life. But there is no unifying presence. Sure, you can expand on the culture however you want for your fiction or your personal journal or whatever, but it will still be only for your version of the culture.
If you are part of one of the costuming clubs, you can see if that particular group has a recommended symbol for use by members of that group. The more people who use a common symbol, the more people will recognize it as such. For example, various MMCC clans have had "autism awareness" patches in the past, though nothing is currently available. Regardless, the ones that did exist are mostly in English with Earth symbolism on them, because that is more likely to be understood by Earthers.
Mir'shupur is evocative. With very few words, it describes the person's situation: the brain is injured and isn't working properly. People know that an injured person needs help accomplishing tasks that the injury makes difficult.
People who practice the Resol'nare on Earth use mir'shupur to talk about any mental illness or challenge regardless of whether the people who have such traits were soldiers or how they received the injury or whether their mental challenges were the result of an injury at all. The folks in charge of MandoCreator even added "mental illness" to the definition precisely because of this expansion of the word on Earth.
One thing about PTSD is that, based on what has been presented about in-universe Mandalorians so far, it's something that so many members of the society would have that there is no need for a special symbol in-universe. Of course, you don't sneak up on a Mandalorian without expecting to be shot. Of course, you don't set off explosives unless you're blowing something up and you've warned your vode about it. These kinds of things are part of social traditions that are part of educating "children" (regardless of age) on being Mandalorian. This kind of information is not something that was described in any detail in the material written by Karen Traviss, so we can only speculate on specifics. That being said, life is different on Earth; Earth Mandalorians exist as largely isolated members of larger societies.
If you want a Mando'a word to describe a different effect than is covered by mir'shupur, think about what you want strangers to do to or for you when they see whatever symbol you chose during brief interactions with you. How do you want the store clerk or the waiter or librarian or whatever to act around you? Focus on words related to that. Remember that the sigil is not meant to cover an extensive list of accommodations that a person needs in order to be a long-term functioning member of a team; save that for the job interview.
An alternative approach to that is to create a word or epithet that is meaningful to the individual. Use it as a way to provide an opening for conversations about specific needs and experiences.