Even before a knife-wielding man attacked a group of elementary school students in Kawasaki on Tuesday, Japan had already seen news of children dragged into dreadful circumstances this year.

Earlier this month, a vehicle plowed into a group of toddlers on a sidewalk in Shiga Prefecture, killing two 2-year-olds and injuring 13 people. In April, an 87-year-old driver rammed into pedestrians in the Ikebukuro district of Tokyo, fatally striking a 3-year-old girl and her mother and injuring nine.

Although Tuesday's attack, which left an 11-year-old girl and a 39-year-old father dead, differed in that it was a mass stabbing, all could be described as distressing events. And children are more at risk of suffering severe mental trauma, said Dr. Toshiko Kamo, a Tokyo-based psychiatrist.