The effects of a vitamin supplement on the pica of a child with severe mental retardation.

One child with severe intellectual disability and anemia kept eating non-food items.

Doctors gave a daily multivitamin with iron and used an ABAB design.

They measured pica across baseline, vitamin, withdrawal, and vitamin again.

When the vitamin was given, pica almost stopped.

When it was taken away, pica returned.

The pattern repeated, showing the vitamin, not chance, caused the change.

Ball et al. (1985) also worked with severe ID, but used flexible arm splints to block finger biting.

Both studies used single-case designs and cut dangerous behavior fast.

The 1985 team chose a mechanical barrier; Mueller et al. (2000) chose a pill.

The choices do not clash — they show different tools for different topographies.

Before you start extinction or response blocking for pica, ask the doctor to check iron and vitamin levels. A simple daily multivitamin dropped pica to near-zero in one child, saving hours of behavioral treatment. If labs are low, a pill may do part of the work for you.