Community (usually school) samples
| Country | Rate (%) | Note | Reference |
|---|---|---|---|
| CTRS, Conners’ Teacher Rating Scale. | |||
| Japan | 7.7 | School; DSM-IIR | Kanbayashi et al20 |
| China | 1.9–13 | Range of studies | Li et al21 |
| 3.0 | Primary school children; DSM-III | Tao22 | |
| Israel | 5.0 | CTRS | Margalit2 |
| Italy | 3.9 (“likely cases”) | Fourth graders; DSM-III R | Gallucci et al23 |
| 6.9 (“possible cases”) | CTRS | O’Leary et al24 | |
| 12.0 | |||
| Spain | 16.0 | CTRS | Gingerich et al3 |
| Germany | 8.0 | CTRS | Gingerich et al3 |
| Iceland | 5.7 | School; DSM-IV | Magnusson et al25 |
| Scotland | 4.5 | CTRS | Gleeson & Parker26 |
| UK | 16.6 | DSM-III | Taylor et al27 |
| The Netherlands | 9.5 | DSM-III | Verhulst et al28 |
| Canada | 5.8 (boys 9%, girls 3.3%) | Ontario, multiple checklists | Szatmari et al29 |
| USA | 9.1–12.0 | DSM-III (4 studies) | Studies reviewed by Faraone et al4 |
| 7.1–12.8 | DSM-III R (6 studies) | ||
| 11.4–16.1 | DSM-IV (4 studies) | ||
| Columbia | 16.0 | Children in the general population; DSM-IV | Pineda et al30 |
| Brazil | 5.8 | School; DSM-IV | Rohde et al31 |
| Australia | 12.0 | Queensland; CTRS | Holborow et al32 |
| New Zealand | 15.0 | CTRS | Werry & Hawthorne33 |