ONDA Koichi Jichi Medical School, Department of Psychiatry, Assistant, 医学部, 助手 (30332985)
KAMADA Yoshiro Jichi Medical School, Department of Psychiatry, Assistant, 医学部, 助手
NIBUYA Massashi Jichi Medical School, Department of Medicinre, Assistant, 医学部, 助手 (00228256)
(Introduction) It had been documented that stress sensitization may be important in the development of schizophrenia. Stress-Vulnerability model has been proposed. However, there are few techniques available to examine exposure to stress stressful experiences during premorbid period which may be critical pre-adulthood brain maturation. The microstructures of unerupted developing enamel cannot fully recover after exposure to stressful experiences, which are accompanied, as a rule, by a drop in trophic parasympathtic stimulation of the ameloblast tissue. Such a stress rings in human dental enamel are markers prior environmental adversity in forensic science, which are conceptually akin to tree rings. Ameloblast Stress line (ASL) may provide estimates of neurobiological relevant pre-adulthood stress experienced by schizophrenia research participants.
(Methods) We examined ASL in third molars in 14 chronic paranoid schizophrenics (12 males and 2 females, 40.1±11.5 years old) and 16 normal c
ontrols (16 females, 30.7±10.2 years old). In National Cednter for PTSD in Honolulu, ASL of 8 patients with PTSD were compared with 36 normal controls. The length of ASL in dental enamel in the third molars may reflect impact of stress, and thus the length and boundary of ASL might provide overall severity of stressors. ASL was assessed using the following 5 point-rating scale (0=none, 1=slight, 2=mild, 3=moderate, 4=severe).
(Results) We have found that 100 % of schizophrenics and 58% of normal controls exhibited ASL. ASL scores in the 14 schizophrenics (8.9±5.5) were significantly higher than the 16 controls (1.6±1.4) (Mann-Whitney U test, p<0.001). Schizophrenics exhibited ASL indicative of stressors experienced during 10-12 years old. The 16 normal controls exhibited the highest ASL scores at age 9. While, the 14 schizophrenics showed the highest ASL scores at age 11.5. The 8 patients with PTSD were significantly more ASL than the 36 normal controls.
(Conclusion) The findings suggest that stress sensitization may be developed between 10 and 12 yeas old at a peak period of age 11.5. ASL may have potential as a cost-effective laboratory estimate of PTSD and schizophrenics' pre-adult adverse experiences during critical pre-adulthood brain development. Less