Complex sentence: Throughout its history, resistance has caused significant division between psychologists, thus it remains a debated issue as there are some who considered it to be merely a description of a patient's temperament rather than a universal construct of the human mind.
Split into simpler sentences: Throughout its history, resistance has caused significant division between psychologists. It remains a debated issue as there are some who considered it to be merely a description of a patient's temperament rather than a universal construct of the human mind.