This invention relates to treating Prader-Willi Syndrome (PWS) using a KATP channel opener. The channel opener may be coadministered with other therapies used to treat PWS, such as human growth hormone, a wakefulness promoting agent, or a psychiatric or mood stabilizing drug, thereby allowing the baseline dosages of these other therapies to be decreased or making these other therapies unnecessary. The invention also relates to treating PWS based on the PWS nutritional phase of a patient, to prevent the patient's PWS nutritional phase from progressing or shift the patient's PWS nutritional phase back to an earlier phase. The invention further relates to treating PWS, and conditions associated with low basal metabolic rate or hyperphagia, with the KATP channel opener based on a patient's blood ketone levels.
