Abstract: Objective To determine the best time for assessing mental disability due to brain damage. Methods Ninety-three mental disabilities due to brain damage in traffic accidents were assessed and their follow-up studies were taken in different period after the brain injury: 3 months, 6 months, 9 months and 12 months. The patients′ brain imaging, electroencephalogram (EEG) and detailed medical history were collected. Then to interview the patients′ family members and to assess the patients′ mental conditions with Wechsler Adult Intelligence Scale(WAIS), Social Disability Screening Schedule(SDSS), and Activity of Daily Living Scale (ADL). Diagnosis and disability assessments were based on all of the above infor- mation. Results ADL and SDSS had good distinction between different levels of disability and different time. The overall sample demonstrated that there was no statistically significant difference between pa- tients′ ADL and SDSS averages in 9 and 12 months. For mild disability, there was no statistically signifi- cant difference between ADL and SDSS averages in 6, 9 and 12 months. For moderate disability, there was no statistically significant difference between ADL and SDSS in 9 and 12 months. And there was no statistically significant difference between ADL and SDSS averages in 6, 9 and 12 months for severe dis- ability. Conclusion For mild disability, it is recommended to assess the mental disability 6 months after the injury, for moderate disability, it is 9 months. The statistics data recommended that the best assess- ment time for severe disability is 6 months after injury. However, our comprehensive analysis concludes that the suitable time is 9 months after injury.

Key words: forensic psychiatry, mental disorders, brain injuries, accidents, traffic, disability evaluation, ADL, SDSS