Officials from Trenton Psychiatric Hospital say they have imposed new security measures to keep patients within the compound and prevent unauthorized walkouts.

Around 80 patients left hospital grounds without permission in 2006, including the high-profile escape of convicted kidnapper Edgar Rene Del Cid Perez.

?We've had to take a real strong look at the risk level of folks, as well as what type of security a hospital can offer,? said Assistant Commissioner Kevin Martone, of the New Jersey Division of Mental Health Services.

Administrators say new security measures include reinforcing fences with green wire mesh and windows with metal grating to prevent them from becoming escape routes. Guards are also placed at all four entrances to the hospital.

So far this year, hospital officials say the number of patients that left hospital grounds has dropped to six due to the security changes.