How can I overcome academic "researcher's block"? I work as a senior academic in an important university in Europe. My name is in several publications in top journals in my field. 

I have always published papers together with brilliant collaborators who really made the difference but they are not there any more.

I am working on a new paper as a solo author but I am suffering a mental blockage and serious problems of anxiety. 

I have previously published some papers as a solo author but I need help with this new paper. The difference now is that I am not able to start writing the proof demonstrations and therefore I cannot attract collaborators. Blank page syndrome. When I try to work on it, I have panic attacks. It's not a lack of skills because I have previously performed at a high level, I am blocked because I am used to collaborative work and talk about work helps me develop my ideas. I am now in a vicious loop, without proofs to attract collaborators and without collaborators to develop proofs

I was invited to give a seminar on my previous paper in an American university. I could use that opportunity to talk with them about my new ideas. I also spoke with some of my department colleagues. They are waiting for me to develop a bit more the proofs to decide whether my idea is feasible and collaborate. They are busy and will not help me at the moment. Right now, I am alone with my unsolved proof and my panic attacks.

Two questions:


How can I overcome this mental block when working with theoretical mathematics? 
My job is my life, I don't want to leave academia but this situation is killing me. Should I leave academia or stay regardless the consequences?
Forgive me but I'm going to just wildly speculate here and hope that you find a bit of value in it. Perhaps you are just the sort of thinker that thrives on the synergy of working with others and getting ideas bounced around and reinforced (or shot down). That doesn't make you less of a mathematician, of course, but just represents one way of getting all of the pieces together. 

It seems like you thought of yourself up to now as the 'junior' member of your circle and now the others have died or retired and so you are left 'alone'. In fact, IMO, you are left, now, as the senior member, but you don't need to continue to be the 'only' member. 

Try to build up the circle again with new junior members with whom you can interact, building up their ideas as well as your own. It will give you that synergy again, if this is indeed the issue (like I said, speculative). A local circle is best, of course, but today's communication resources give additional options if learn to use them intensively. 

And you have the opportunity to become the master that those younger scholars look up to and revere as they grow into the profession. Very cool. 



One additional factor might be at play. When a person tries too hard for too long at intellectual activity, the brain sometimes rebels and shuts down. A break is called for, especially a break that gets the blood flowing, such as physical exercise. Physical exercise that also engages the brain but in a different way from the normal research mode can be helpful. I use Tai Chi for this as it is a mind-body fusion exercise, though not aerobic. When younger, I used cycling and x-c-skiing and such though they didn't have the same mental component. But an hour or so break for physical exercise can sometimes invigorate you. 

And since the mind works subconsciously as well as when forced, sometimes insights magically appear during or immediately after a break. Even a sleep break.