Allah gave us a way to renew bliss in our lives every week, this can help decrease the symptoms of depression among other things, and puts a joy in your life you would otherwise miss.
Reading Suah Kahf (Quran Chapter 18) (http://quran.com/18) on Fridays is one of the best deeds you can do, it not only illuminates your life, but it offers protection from the comming Dajjal (anti-christ), of which we have no idea when he will make his appearance.
The hadith related by Hakim and Bayhaqi, from Abu Sa`id (Allah be pleased with him), “Whoever recites Surat al-Kahf on Friday, light shall shine forth for him between the two Fridays”. [Ibn Hajar, Talkhis al-Habir]
Imam Shafi`i (Allah have mercy on him) said in his Umm,
It has reached us that whoever recites Surat al-Kahf on Fridays will be protected from the Dajjal. [Shafi`i, al-Umm, 1.239]