The US Preventive Services Task force just released data findings this past Tuesday that indicates that certain mental health screenings could be useful for children as young as 8. However, despite a growing mental health crisis among children of all ages, the group said it could not find enough scientific evidence to support regular screening for anxiety among children younger than 8 years old or screening for depression in children under 12.
The USPSTF draft recommendation is available here: https://www.uspreventiveservicestaskforce.org/uspstf/
Best,
Paul