What signs do we have that Willy is in an unhealthy mental state?
Many of the signs that Willy exhibits is reflective of an unhealthy mental condition. Willy's grip on reality is loosening. His indulgence in flashback is so intense that it is not merely a stage direction. In an authentic way, Willy jumps between the past and present, with an indulgence in the former that indicates his inability to deal with the latter. The imaginary conversations he has with Ben are an example of a mental health that is far from solid. Willy's highly emotional and and unstable state of being is another indication that Willy is not doing well from a mental health point of view. He is unable to establish anything real and transcendent. Willy has embraced the contingent and transitory as permanent. The result is that his construction of reality is not mentally sound. It is for this reason that he can justify suicide with so much ease: ""Why? Does it take more guts to stand here the rest of my life ringing up a zero? ... And twenty thousand—that is something one can feel with the hand, it is there."
Such a statement helps to indicate much within Willy that is not mentally sound. Willy's continual belief in a mythological "American Dream" has caused him to move to a mental condition where little is of sound judgment. This unhealthy mental state is what helps to define his character in a distinctive way. Rather than admit the reality of the forces around him, Willy's mental state has deteriorated into one where he still believes that he can define his subjectivity in accordance to a reality that does not exist. It is for this reason that there are many signs that Willy is in an unsound mental health state.