Panetta spoke on Friday to mental health professionals who are focusing on reducing suicides by veterans and soldiers.
Pentagon statistics indicate that the rate is about one suicide per day this year.
Panetta notes that more than half of the military members who committed suicide have no history of deployment. He calls the problem perhaps the most challenging one he's faced on the job.
He says part of the solution lies with commanding officers, and he says they have to ensure that those who seek help will not be ostracized.