Sentence:  While some suppression and some denial are not only necessary but healthy , the worker 's clinical knowledge must determine how these defenses are being <WSD>used</WSD> , what healthy shifts in defensive adaptation are indicated , and when efforts at bringing about change can be most effectively timed . 
Meaning of the word marked with <WSD> tags:  put into service; make work or employ for a particular purpose or for its inherent or natural purpose