All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is not permissible for a Muslim individual to abandon fasting during Ramadan except due to a sharia-approved excuse, such as an illness that makes one unable to fast. However, after recovery, one has to make up for the days that he failed to fast during Ramadan. This is because Allaah Almighty says (what means): {So whoever among you is ill or on a journey [during them]—then an equal number of days [are to be made up]...} [Quran 2: 184]
As for the condition of this person, it is not a valid excuse for abandoning the fast. Fasting is not the reason behind his psychological problem; rather, it is something else. That is because fasting is a source of psychological comfort for the believer. Perhaps khat or cigarettes are the real reason for his problem, or maybe he is possessed by jinn, which might make him feel annoyed when he offers an act of worship. Thus, he should be treated with sharia-approved ways of treatment and not abandon fasting on account of this matter since his fasting involves subduing and overpowering the devil. If cigarettes or khat is the reason behind this, then he has to strive against himself so as to give up using those and make the best use of this month so that it may help him to leave such evil. The means to fulfill that is by busying himself with other matters that make him forget them. Besides that, he should stay in the houses (i.e. mosques) of Allaah Almighty, to recite Quran, remember Allaah Almighty a lot, sit with righteous people, keep away from evil gatherings that help him do evil things, and make much supplication for the fasting person has an answered supplication upon breaking his fast.
As for your statement, “the religion is easy,” it is really correct, and there are many texts reported in this regard, and Muslim scholars have agreed upon it. However, leaving the obligations that Allaah Almighty has imposed without a sharia-approved excuse has nothing to do with the easiness of the religion.
Allaah Knows best.