Screens allow you to keep the windows open, but prevent your cat from falling out of the windows. [substeps] If you rent your home and can't install screens, consider purchasing an adjustable screen insert that will fit into the open window.
[header] How to prevent feline high rise syndrome [title] Secure your windows. [step] If you frequently open your windows, install window screens. These should fit snugly over the window, so there are no gaps.