Introducing one or more stimulating drugs to the brain and/or applying electrical stimulation to the brain is used to treat epilepsy. At least one implantable system control unit (SCU) produces electrical pulses delivered via electrodes implanted in the brain and/or drug infusion pulses delivered via a catheter implanted in the brain. The stimulation is delivered to targeted brain structures to adjust the activity of those structures. The small size of the SCUs of the invention allow SCU implantation directly and entirely within the skull and/or brain. Simplicity of the preferred systems and methods and compactness of the preferred system are enabled by the modest control parameter set of these SCU, which do not require or include a sensing feature.