The aim of this review is to present the main diagnostic uses of startle from the fetal period to adolescence. In the first stages of development the startle is mainly used as a neurological marker of neurological dysfunctions. By the analysis of some clinical indices (such as appearance frequency, onset latency, simmetry, etc.) the startle can be used as a rapid antepartum test to predict fetal well-being and, in the neonatal period, as a clinical tool in the diagnosis of specific neurological pathologies or syndromes. In the following stages of development, from preschool age to adolescence, the clinical use of startle is mainly linked to the eziogenetic study of affective disorders. The startle is indeed a reliable vulnerability marker (Merikangas, Avenevoli, Dierker, & Grillon, 1999) for children at risk of affective disorders, in particular anxiety disorders.
