Although repression thus functions as a vital coping tool, it also can cause great anguish. A repressed urge of the id, though it may be in the unconscious, still affects the actions and thoughts of the individual. Indeed, conflicting urges or painful memories thus repressed have the potential to cause great anxiety, though the individual will not understand what causes it. As the repressed items teem and surge beneath the conscious surface, they sap vital psychic energy and constantly force the individual to maintain lines of defense mechanisms against his own unconscious. But as the urges boil up, the individual eventually will find release, through some external displacement, displaced emotion, or other mechanism. This release, coming as it does from uncontrollable and often unfathomable depths, can cause unpredictable, sometimes unimaginable reactions. The repression causes anxiety, discomfort, even neurosis; the cathartic release causes massive emotional and often physical damage.

This seems OK as written. Why do you want to paraphrase it?

Or are you asking for help in understanding it?

I want to change it in a more simple way..