Modafinil is in a class of supplements known as eugeroics. Modafinil is actually a chemical stimulant, although its specific mode of action is not entirely understood. Even though it does not appear to work in a similar fashion to caffeine, there is a big interest in this supplement from those who are having sleep problems since it can be useful for staying awake and alert. Of course, this also raises the question as to whether or not Modafinil actually disrupts sleep.
Why Modafinil Is Used:
The main and stated clinical use of this supplement is for helping with narcolepsy. However, many people use Modafinil for a number of sleep problems and issues. People with sleep apnea who are using continuous positive airway pressure therapy to deal with sleep apnea will wake up and not feel rested on a regular basis. The thought is that this supplement can help. Also, people who work night shifts sometimes find it helpful to use such a supplement in an effort to stay awake.
Anecdotal Evidence for Modafinil and Sleep Disruption:
A number of Modafinil users have discovered that it can at times be a disrupting influence during the night. This seems to occur more frequently the later in the day (or evening) that it is taken. Generally, the solution for this problem is to only use the supplement in the mornings, since the intention is indeed to increase wakefulness and awareness, preventing sleep.
Other users say that the reason for waking up and not feeling refreshed while using this supplement is due to taking too high a dose. As with anything, you do want to make sure that the lowest effective dose is used, even if this means splitting a tablet into two. Another method to avoid having the sleep cycle disrupted is by cycling on and off of Modafinil. Maybe use something like a 2-days on, 1-day off schedule to keep the brain and the body guessing.
Conclusion—Modafinil and Sleep Disruption:
Ultimately, whether or not Modafinil will disrupt sleep schedules comes down to how you use it. By being careful and taking the lowest effective dose you should have a much better chance of seeing only the positive effects you are looking for. Also make sure not to take this during the evening, since it is a very powerful substance and can last a while in the system.