Senile dementia is defined unsatisfactorily as deficiency of memory and orientation, plus confabulations. It gives insufficient understanding of demential behaviour. This behaviour is characterized by mistakes and wrong compensations in daily living activities in aged people, everybody with his own life-history, own particularities and own psychosocial situation. This behaviour is understandable from disorders of memory, comprehension and initiative, but isn't identical. There are many different conceptions about the origin of dementia] behaviour:

1. deficit-conception;
2. neurological (dementia = neuropsychological deficiency);
3. anthropological (dementia = deficiency of human qualities);
4. lowering of mental level;
5. burden exceeds capacity;
6. defense and coping mechanisms;
7. environmental problems, e.g. family tensions;
8. negative attitude of society;
9. disturbances of cybernetical mechanisms;
10. disturbances of sub- or suprasystems and of informationcycle (General system theory).

We can never understand completely or treat a human being with demential behaviour without detailed information about all these fields, and without an attempt to bring all in a certain structure.