I'm currently 70% for PTSD. I've been diagnosed with sleep apnea by the VA and have been issued a CPAP machine. I've been using the CPAP for over three years. I asked my a PCP if he would write me a nexus letter but he said that would not. He said its a conflict since he works for the VA. Can anyone tell me if that is true? What can I do? Can I request a different doctor within the VA to write me a nexus letter to help support my claim. Since I'm already SC 70% PTSD and have the CPAP machine what are my chances of getting the the sleep apnea SC as secondary.