It is widely acknowledged in psychiatry that there is such a thing as generalized anxiety disorder - the condition of being constantly to anxious for the circumstances. There are a number of drugs to treat it.
Studies of unipolar depression likewise point to one common chain of causation being sustained over anxiety, which, if it lasts too long, caused the anxiety/stress system to shut down entirely leading to depression.
But, surely, if many people have a tendency to overreact and become too anxious, other people must have the problem that they aren't anxious enough, that they are calm when they should be agitated with anxiety and driven to take action. Anxiety, like fear and pain, exists for a reason. It has an important purpose. Not having enough can surely sometimes be just as harmful or moreso than having too much. Surely, inappropriate calm a.k.a. indifference, can be a problem as well.
Why then, are there no pro-anxiety or anxiety amplifying or enhancing drugs out there for them? Are people who have insufficient anxiety simply not diagnosed because the DSM-IV doesn't acknowledge the problem, or because people who have it and are disabled as a result are misdiagnosed?