A. Lundy et al., UNDERREPORTING OF COCAINE USE AT POSTTREATMENT FOLLOW-UP AND THE MEASUREMENT OF TREATMENT EFFECTIVENESS, The Journal of nervous and mental disease, 185(7), 1997, pp. 459-462
Substance abusers, especially cocaine abusers, may underreport their s
ubstance use in outcome interviews. Follow-up interviews were conducte
d and urine specimens were obtained on 633 persons 9 months after admi
ssion to a 3-month cocaine treatment program. Although 422 (67%) repor
ted no use of cocaine in the past 30 days, 134 of these (32%) had coca
ine-positive urines. This group did not differ on most characteristics
at intake or follow-up from the 288 with cocaine-negative wines. The
amount of treatment received did affect willingness to admit drug use.
Of 132 treatment completers who reported no cocaine use at follow-up,
21 (16%) had positive urines. Of 91 early dropouts who also reported
no cocaine use: 36 (40%) had positive urines. This differential rate o
f underreporting had the effect of seriously underrepresenting the eff
ectiveness of treatment completion as compared with little or no treat
ment.