Some of these consequences have already been explored in the literature while some of them still have to be studied. The psychological aspects associated with moving to another country have also received serious attention from the scholarly community. The phenomenon of 'culture shock' was among the first seriously studied issues associated with the psychological consequences of international immigration.
The term 'culture shock' was coined by Olberg (1955) who used it to refer to the difficulties of acculturation and adjustment among US workers involved in a health project in Brazil. One of the most interesting studies in the field of culture shock belongs to Ishiyama's (1989) whom listed and structured the variety of psychological consequences related to this phenomenon, and proposed a specific model of self-validation eventually used in a number of other similar studies conducted by European and American researchers.
Ishiyama argues that culture shock from moving to another country involves 'invalidation' of the person's past experiences: "The process of adjusting to a new cultural and social context inevitably challenges, confuses, threatens, and invalidates to varying degrees individuals' previously achieved sense of identity and self-worth and their feelings of security and comfort of living in a familiar environment" (Ishiyama, 1989: 43). The researcher identifies the following areas of the invalidated experiences: (1) security, comfort and support; (2) self-worth and self-acceptance, (3) competence and autonomy; (3) identity and belonging, and (4) love, fulfilment and meaning in life. The essence of the model proposed by Ishiyama is the following. The change, coupled with the need to adjust to a new cultural environment does not only mean the necessity to accept new social norms and values, language, and ethics, but also transforms the intrapersonal dimension of the person thus negatively affecting her self-worth and self-value. Therefore, the transformation often results in psychological trauma, feeling of loss, excessive emotionality, and other negative psychological consequences. Ishiyama's findings are fully congruent with the previous research in the field (Lysgaard, 1955; Gullahorn & Gullahorn, 1963; Berry & Annis, 1974; Church, 1982; Berry & Kim, 1988) and have been confirmed by a number of more recent studies (Pedersen, 1991; Thomas, 1995).
A solid attempt to investigate the gender aspects of the impact of moving to another country on self has been recently undertaken by Walsh and Horenczyk (2001). The study represents an examination of the aspects of different self-related experiences immigrants may go through with particular reference to gender differences. The authors identify two major challenges associated with moving to another country: the need to feel a sense of belonging and the need to feel competent in the new environment. Each of these challenges rests on a different self need which majority of the participants felt broken, damaged or seriously affected by the transition to an alien country. However, the authors observed a distinct tendency when men and women tended rank these two self needs