Insomnia Is lack of sleep and might be caused especially my chewing too much 'khat'. Khat has been known over the years to cause some sleeping deficient. I personally have tried it and can testify it's true. Also, another reason could be, taking too long naps. You might find that at times you decide to take naps but forget to put a wake up alarm and you end up taking naps for almost 3hours. This has effects because when the it comes to sleeping time, you'll find it hard getting some sleep. Still on the naps, its not advisable to take naps late in the evening. This has been found to be one characteristics of insomnia. The only prevention measure is reducing the time you take naps, 20 or 30 minutes naps is awesome. Also, avoid using such kind of drugs which might cause insomnia.