Forced-swim test (FST) evaluation of WT and YAC128 mice. 11-month-old mice were individually placed into a beaker of water (23-25°C) for a total of 300 secs and videotaped. Total immobility time of each mouse after the first 120 secs was manually scored by an experienced experimenter who was blinded to the genotype and drug treatment of the mice. YAC control group recorded significantly greater FST immobility time than WT control group (p < 0.05). Feeding TBZ to WT mice increased immobile than WT control mice (p < 0.05). Early-feeding TBZ to YAC mice exhibited more immobile compared with control YAC mice (p < 0.05). Late-feeding TBZ to YAC mice had no significant effect on depression-related behaviors compared with control YAC mice. ns, not significant.