I have always wanted to put my finger on the difference between pessimism and negativism, because people often use the terms wrong when pointing to someone. To make this writing easy for me we are gonna use the terms “N type” when referring to negativism and “P type” when referring to the pessimism type.
The biggest confusion that people make is taking a worried man for a P type guy. Well this is how I see it: pessimism reflects the view upon a human being entire life, and can hardly be change; on the other side negativism reflects a persons view upon the period of life in wich that person is, present and the near past and future. But the main difference between this two states of mind is that, when having a clear mind the N type still can see the light at the end of the tunnel, meanwhile the P type will never see that light.
P type, in my opinion it also has a genetic heritage, while the N type can be caused by a over thinking and over analysing person.