Subtract the waking cortisol value from the value 30 minutes later, and the difference is treated as a marker of how well the body gears up for the demands ahead. Earlier work by other groups had reported a blunted CAR in frequent cannabis users. Subjective stress was positively related to waking cortisol across the whole sample, at p = 0.001. Higher awakening cortisol tracked with cannabis-related consequences, the negative outcomes people report from their own use, at p = 0.007. It is calculated by subtracting the waking value from the 30-minute value and is used as an indicator of stress-system function.