After a brief historical background, the authors have illustrated the INSERM research (originating in France) which was subsequently joined by a group of Italian researchers (including the authors). The aim of the research was to measure the evolution, or stagnation, of autistic children in psychotherapy over the arc of a year, at 2-, 6-, and 12-month intervals. The work examined not only whether or not attitudes and behaviours changed, but also the underlying process and the quality of the therapist-patient relationship as it developed. After a description of the methodology used, the results that emerged from the analysis of the first 50 cases have been discussed. From these results, it has emerged that not only can psychotherapy impact significantly on the development of children with au-tism, but also that it is possible to carry out strictly scientific assessments, without negatively impacting on or impairing the analytical work. A case has also been presented with double description method, including a conventional narrative description of a clinical case and an experimental ap-proach based on empirical research.