In this DataWatch we examine whether the passage of California's Propo
sition 187 affected the use of mental health services in San Francisco
County. Using time series analyses, we identified a 26 percent decrea
se in the initiation of outpatient mental health services by younger H
ispanics at selected service sites after the passage of Proposition 18
7 in November 1994. Further analyses suggest that decreased use of out
patient mental health services by young Hispanics was associated with
their subsequent increased use of crisis services. Other studies of Pr
oposition 187's effect on mental health service use in California are
needed to corroborate the findings of this case study.