Sometimes the cries for help are virtually impossible to miss. An angry child sets fire to his parents' bedroom. He tortures a helpless cat. Or he smashes the windows of the school building.

But when the warning signs are veiled jokes or threats, a common, often innocent part of an adolescent's life, social workers and teachers say detecting a serious problem is trickier.

"If more kids were referred {to social workers) by parents, teachers and friends who think their friend was acting weird, if they talk to kids beforehand, the situations could be defused," said Wynne Crosby, president of the Illinois Association of School Social Workers, an organization whose membership has almost doubled in the past decade.