stressor

Emotional First Aidを読んでいます。
These two systems are located primarily in the anterior cingulate cortex and prefrontal cortex, regions of the brain I have described in earlier chapters. These regions are also responsible for such executive functions as self-monitoring, coping with stressors, making decisions and weighin alternatives, all of which draw on the same limited energy source.
ストレスは日本語になっていて、代わりの日本語は思い浮かびません。"stressors" はストレスを与える原因、要因であることも直ぐに分かりますが、日本語でストレッサーと言うのは聞いたことがありません。日本語ならやはりストレスの原因あるいはストレスの要因となるのでしょう。
・Collins Dictionary: an event, experience, etc, that causes stress: The problem seems to be more severe and last longer when the stressor is of human design, like the one you encountered.
・Merriam-Webster's Online Dictionary: a stimulus that causes stress: Examples of stressor in a sentence: Credit card debt is a major stressor in her life.