The MBD rating system evaluates loss of function from a mental or behavioural disorder in the following key areas: 1) Activities of daily living; 2) Social functioning; 3) Concentration, persistence and pace; 4) Deterioration or decompensation in work or work-like settings. For collisions after June 1, 2016, a person must experience impairment levels that significantly impede useful functioning (“Marked” impairment) in 3 of these areas to qualify.