EX-1
from SC 13D
1 page
Exhibit 1 Joint Filing Agreement the Undersigned Hereby Agree That the Statement on Schedule 13d Filed by the Undersigned With Respect to the Common Stock of Neurogen Corporation Is, and Any Amendment Thereto Signed by Each of the Undersigned Shall Be, Filed on Behalf of Each Undersigned Pursuant to and in Accordance With the Provisions of Rule 13d-1(k) Under the Securities Exchange Act of 1934, as Amended. Dated: April 21, 2004 Warburg Pincus Private Equity VIII, L.P. By: Warburg Pincus & Co., General Partner By: /S/ Scott A. Arenare Name: Scott A. Arenare Title: Partner Dated: April 21, 2004 Warburg Pincus & Co. By: /S/ Scott A. Arenare Name: Scott A. Arenare Title: Partner Dated: April 21, 2004 Warburg Pincus LLC By: /S/ Scott A. Arenare Name: Scott A. Arenare Title: Managing Director
12/34/56
