Chronic paroxetine treatment (10 mg/kg/day for 14 days) reduces social fear in ASM+/+ and ASM+/− mice but not in ASM−/− mice. (a,d,g) Preconditioning investigation of the non-social stimulus (empty cage) shown by unconditioned (SFC−) and conditioned (SFC+) mice during SFC on day 1. (b,e,h) Number of foot shocks received by SFC+ mice during SFC. (c,f,i) Investigation of the non-social (ns1–ns3) and social (cages with mice; s1–s6) stimuli during social fear extinction on day 16. Paroxetine (Par) was administered over 14 days in the drinking water (W) starting one day after SFC. Data represent mean ± SEM, and numbers in parentheses indicate group sizes. p < 0.05 * versus all groups; # versus SFC−/W.