One factor contributing to unclean thoughts is anxiety
coupled with lack of dependence on God; for this reason,
many students complain of domination by unclean thoughts during examination periods — their busiest time of year. In their anxiety, they try to escape from reality by resorting to unclean thoughts. A strong remedy against such thoughts is prayer, so that the Lord may grant you peace, internal joy, and reliance on Him.

From Heart to Heart
Fr. Tadros Y. Malaty