I've suffered from bouts of target panic over the years, and still get it from time to time. I'm sure there are people who have had worse cases than mine, such as Shakes's friend. Since I haven't walked in their shoes, I can't speak for them. But, logically speaking, if we're talking about a condition where you can come to full draw and hold on a target you don't intend to shoot at, but can't come to full draw and hold on a target you do intend to shoot at, it has to be a 100% mental condition.
I'm sorry that Shakes's friend quit archery over it, because I believe TP can definitely be cured, if not permanently, then at least for a while, and if it comes back, it can be cured again.
There are people out there like Jay Kidwell and Joel Turner who have made great contributions to understanding and curing target panic. There are whole fields of Eastern philosophy and both Eastern and Western religious teachings that deal with calming your mind and controlling your passions. People who want to badly enough have managed to overcome much harder things, like smoking, drinking, and drugs. People have learned to control their anger and their addictions to sex, gambling, spending binges, and other types of compulsive behavior.
The common thread in all these addictions, and TP is an addiction, is that by the time a behavior becomes an addiction, it is usually impossible for someone to overcome it on their own. If they could have, they would have stopped it before it became an addiction. So you have to be willing to reach out and seek help from knowledgeable sources.
The second common thread is that one size doesn't fit all. Joel Turner may work for one person, Jay Kidwell for another, Eastern mind control for another, and so forth. I thought I had it licked by focusing my awareness on what my body was doing during the shot and avoiding all cognitive thoughts during the shot. However, halfway through a tournament last weekend, I found myself rushing the shot and unable to complete my shot sequence the way I wanted to. Each time before I would draw the bow, I would tell myself that the result wasn't important; the important thing was executing my shot sequence. And yet, right after telling myself that, I would rush the shot anyway.
Finally, I remembered Joel Turner saying in his DVD that most of the time he really didn't need a mantra, but if he felt his shot sequence slipping, he would start using one again. I didn't think I needed a mantra either, because I thought I had learned to clear my mind of distracting thoughts by focusing on my shot execution. But even though that had worked really well for me before, it wasn't working last Sunday. So I started using a mantra and I was immediately able to complete my shot sequence without being rushed.
I'm not using my experience as a recipe for anyone to follow; it may not work for me the next time I try it. What I am saying is that if you keep trying the same old things, you're going to get the same old results. You have to try new things. Even if they don't work, it's got to be better than suffering through half a tournament shooting like crap and wondering why.