The degree of startle response depends on breed and early socialization. (diamondsintheruff.com)
I suffer from PTSD so I have problems with anxiety, occasional depression, random debilitating panic attacks, nightmares and a very exaggerated startle response. (bodyunburdened.com)
Alterations in diurnal cortisol rhythm and acoustic startle response in nonhuman primates with adverse rearing (cambridge.org)