Functional assessment and treatment of pica: a single‐case experiment

Abstract

The pica of a 6-year-old girl diagnosed with autism was initially shown to persist in the absence of socially mediated consequences. In an attempt to provide a competing source of oral stimulation, we used a stimulus preference assessment to identify food items that were subsequently presented noncontingently. However, the noncontingent schedule could not be thinned to a practical variation while still maintaining reductions in pica. A subsequent multielement evaluation of response blocking and verbal reprimands demonstrated that neither intervention both produced and maintained low levels of pica. Verbal reprimands were then used in conjunction with noncontingent food presentation, but this intervention did not produce signi®cant reductions in pica. Suppression of pica was ultimately obtained in both a clinic setting and in the child's natural environment using contingent, varied auditory stimulation. The results are discussed in the context of the`least restrictive alternative' model of treatment selection.

An Analysis of Response-Blocking Parameters in the Prevention of Pica

“…Although pica (the ingestion of nonnutritive substances) represents one form of SIB that is often maintained by its own consequences, response blocking as an intervention for pica has produced mixed results. For example, Rapp, Dozier, and Carr (2001) reported that response blocking (when used independently) did not reduce pica to clinically acceptable levels and produced aggression as an unwanted side effect. By contrast, LeBlanc, Piazza, and Krug (1997) found that response blocking was just as effective as restraint in preventing a young girl's pica and was associated with less therapist effort and fewer negative vocalizations.…”

A systematic review of the effectiveness of behavioural treatments for pica in youths

“…VRs were used in 11 studies and included verbal utterances informing the youth when their behaviour is undesirable or unacceptable. These utterances ranged from direct instructions (e.g., “not in mouth”; p. 113, Rapp et al, 2001), to shouting “no” at the child (e.g., p. 137, Bucher et al, 1976). Of these 11, five studies that included VR as part of a treatment package effectively reduced pica to near‐zero rates (Bucher et al, 1976; Johnson et al, 1994; Kalfus & Burk, 1989; Piazza et al, 1998, 1996).…”

“…For example, youth can be rewarded with preferred food or toys when they do not engage in pica behaviours (Sinha & Mallick, 2010). Three out of four studies that included CR were effective in lowering pica to near‐zero rates (Kalfus & Burk, 1989; Rapp, Dozier, & Carr, 2001; Sinha & Mallick, 2010). In two of the effective treatments, CR was included as part of a combination treatment with punishment procedures (Kalfus & Burk, 1989; Rapp et al, 2001) and response interruption (Rapp et al, 2001).…”

“…Three out of four studies that included CR were effective in lowering pica to near‐zero rates (Kalfus & Burk, 1989; Rapp, Dozier, & Carr, 2001; Sinha & Mallick, 2010). In two of the effective treatments, CR was included as part of a combination treatment with punishment procedures (Kalfus & Burk, 1989; Rapp et al, 2001) and response interruption (Rapp et al, 2001). Sinha and Mallick (2010) demonstrated that CR was effective as a stand‐alone treatment in reducing pica behaviours during and post‐treatment (1‐year follow‐up).…”

Using differential reinforcement of a discard response to treat pica

“…Attempts to reduce or eliminate pica have involved a range of treatments, from drug (Ginsberg, ) and vitamin therapies (Pace & Toyer, ) to behavioral therapies (Foxx & Martin, ; Goh, Iwata, & Kahng, ). In the behavioral assessment of pica, most researchers have found that the behavior is partially if not completely maintained by automatic reinforcement (Ing, Roane, & Veenstra, ; Mace & Knight, ; Piazza, Hanley, & Fisher, ; Piazza et al, ; Rapp, Dozier, & Carr, ). It is possible that because automatically reinforced behavior is difficult to extinguish and alternative reinforcers would have to compete with the automatic reinforcement produced by the pica itself, some reinforcement procedures alone have not been effective at reducing pica (Finney, Russo, & Cataldo, ; Fisher et al, ; Hagopian, Gonzalaz, Rivet, Triggs, & Clark, ).…”