Stress, as defined in the dictionary, is mental and physical tension or strain. When stress occurs in quantities that the system cannot handle, it produces pathological changes. This biological concept of stress was developed by the late Dr. Hans Selye, who intended originally for stress to indicate the cause rather than the effect. But through a linguistic error, he gave the term stress to the effect and then later had to use the word stressor for the cause. Therefore, it seems that outside influences are not the cause of the inward stress, rather the stress is the result of how we, as individuals, handle the influences from outside.
Some individuals handle stress with ease, others panic or have an anxiety attack more readily.
In other words, stress is a descriptive term for a reaction of how an individual handles pressure and tension, whether from internal or external sources. Constructive handling of pressure and tense situations will result in lesser symptoms of stress and anxiety. Poorly handled or denied reactions will result in greater symptoms of stress and anxiety. Hysteria is extreme reaction to inability to handle situations. Rather than causes here, we will be speaking of the outside influences which may or may not trigger a reaction of anxiety within an individual.