Chicago, Illinois (CNN) – Congressman Jesse Jackson Jr. of Illinois resigned from office Tuesday, ending months of speculation about his future. Jackson has not been seen in public since he took a leave of absence in June to get treatment for severe bipolar depression.

In a resignation letter submitted to House Speaker John Boehner on Wednesday, Jesse Jackson said, “for the past several months, as my health has deteriorated, my ability to serve the constituents of my district has continued to diminish.”