I guess there alot of things that can happen; anxiety can affect people in different ways. For me, when I had my first panic attack it sent me into a 'downward spiral.' I went from being social, active, and loving life to being afraid to leave my home and became depressed. I felt alone and very confused as to what was going on, BUT there are so many tools and ways to learn about the anxiety.
Talking it through with a mental healthcare professional, certain medications, good support groups (like this forum) are all great things I have used to overcome fear of this. Anxiety can just drain you both mentally and physically, but if you arm yourself with the knowledge about it, it is VERY manageable and in many cases makes you a better person and life is just that much more gratifying (even though sometimes the person does not realize it at the time).
Your question reminds me of mys ister and I playing together, and one day she said, "I wonder what would happen if we put this moth in the microwave?"
World's smallest Col. Sanders.
Anyway, to answer your question, consider what cj wrote: "for me."
It is all about individual situations. That said, let me layout a sort of frame work of outcomes. If the anxiety is highly situational -brought on by a particular combination of circusmtances- then the removal of that stimulous may well mean the anxiety never comes back. "That was easy." And that's at one end of the spectrum.
At the other are cases which are rooted in organic, medical, physically present causes which are independent of the thought process and emotional predispositions. These folks, if untreated, are going to have big problems. But precisely because they are so extreme, it is unlikely that they will go untreated -the potholes in their streets are deep and many. That's the other end.
Between is a range of presentations, more or less extreme with more or less interruption of life, sense of well-being, ability to handle relationships and intimacy, career -you name it. And for these folks (which is most of the good people who haunt the hallowed halls of the Anxiety Forum) the question is easily answered because for most, the condition of NOT being treated is exactly what we have faced. That's what got us to the point we sought treatment.
More broadly, we might argue that there is no such thing as "untreated" anxiety or panic, because everyone tries to do SOMETHING about it. The question really is, what KIND of treatment? If we assume that we're talking about medical intervenbtion -the meds, the therapy- then the next question is about WHEN treatment is started or stopped. I regard myself as "cured." I no longer have panic and anxiety and don't expect to ever have it again. I take no meds, do nothing special about anxiety, don't really think or wonder about it -except regarding the forum, of course. But that only means that my mental machinery is self-adjusting, for indeed, the circumstances that once produced anxiety are still around me -it is just that the process of dealing with them is internal and on "auto-pilot," the same as other bodily and mental maintenance operations that fend off the flu, heal a wound, etc.
Taking your question literally -meaning we withdraw treatment from someone who is in the midst of it- there are numerous examples. We get some hint of what happens by reading posts here from folks who are trying to taper off meds on their own -and then the anxiety comes back. Or others who can't afford continuing their treatment or for some other reasons no longer have it available to them. What happens? What happens is exactly what they report happens, right here on this forum.
I hope this answer, while not conclusive, is at least helpful.
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