People, even psychologists, did not recognize psychological stress until Hans Selye's observations transferred the concept from physics to personal circumstances about 1950. Selye observed that patients were suffering physical effects that were not caused directly by their disease or medical condition.
After that the gradual realization dawned that age-old if ill-defined concepts such as worry, conflict, tiredness, frustration, distress, over-work, over-focusing, confusion, mourning and fear could all come together in a general broadening of the meaning of the term. The popular use of the term stress in modern folklore expanded rapidly, spawning an industry of self-help and personal counselling.
The use of the term stress in serious recognized cases such as those of Post-traumatic stress disorder and psychosomatic illness has scarcely helped clear analysis of the generalized stress phenomenon. Nonetheless, it is clear that stress from negative life events, or distress and from positive life events, or eustress can have a serious physical impact distinct from the troubles of what psychotherapists call "the worried well". See General adaptation syndrome.