Some embodiments of the invention relate to a system for delivering to a subject at least one pre-determined amount of THC, the system comprising: a memory which stores a scheduled regimen for delivery of THC to the subject, the scheduled regimen defining: a maximal amount of THC to be delivered, the amount being 0.75 mg THC or less, and a time period within which that amount is delivered, the time period being 2 hours or longer； a decision module which decides, according to the scheduled regimen, if a delivery should take place； and an inhaler device for delivering THC to the subject, the inhaler device comprising a controller which carries out delivery of THC based on the decision made by the decision module.
