In the empirical findings about the stress in adolescence we find different operational definitions of this concept. For the need of this overview the author took Lazarus's (1966) definition that "stress is a threatening demand facing the psychological system". Older studies investigated stress in adolescence on the model of direct effects. Connections were sought between single psychological, that is social, origins of stress with some physiological, affective and behavioral reactions to the stress. Apart from the fact that the results of such studies were sometimes contradictory to the nature and degree of the connections of the anticedent stress variables with the variables - consequences of stress, they were also not complete as an explanation of the stress process. For such explanation it is more advisable to take more complex models by which stress has been studied recently and in which effect of mediational factors are taken into the account for the final results of the stress. The author stress the dangers of of taking such complex models that could lead into the proliferation of new concepts and constructs in this area of investigation in which not even traditional concepts (such as stressor, stress, derangement, suffering, etc.) have neither been explicated nor conceptually differentiated.
