Abstract: Devices and methods for treating central nervous system disorders by administering light to a user are disclosed. In some embodiments, the devices are positioned away from the user, and in other embodiments, the devices are attached to the user. In some embodiments, the light is applied through the users skin, and in other embodiments, through an implanted or percutaneous device. Representative central nervous system disorders include cognitive, motor, and behavioral disorders. Where these disorders include an inflammatory component, light is administered at wavelengths which decrease inflammation in the brain. Where these disorders are caused by poor vascularization, light is administered at wavelengths which improve vascularization in the brain. The methods also include repairing damage to the blood brain barrier, and can be used to more effectively administer drugs, such as anticancer drugs, to the brain.