METHODS
Participants
Data for the current analysis are from a follow-up interview (2010–2012) in a natural history
study of MA use. Subjects are from two cohorts from earlier studies: 1) clients treated in
publicly funded Los Angeles County treatment programs in 1995–97 (n=230 in current
analysis); and 2) a cohort from the same communities who have not previously participated
in formal substance abuse treatment at their original recruitment in 2001–2004 (n=175 in
current analysis). The original treated sample (N=351) was recruited from a stratified (bygender, ethnicity, treatment modality) random sample of 1995–1997 treatment admission
records in Los Angeles County and was first interviewed in 1999–2001, and again in 2001–
04. The original not-treated sample (N=298) was recruited and using community approaches
including an acquaintance sampling approach, key informants, and extensive outreach in a
range of Los Angeles county community venues to achieve socio-demographic and MA use
behavior diversity; they were first interviewed in 2001–04. All participants were English or
Spanish speaking. Detailed description of the treated sample and study procedures can be
found in Brecht et al.20 The first 405 participants interviewed in an ongoing 2009–12
follow-up study who completed the ANAM test battery are included in this analysis.
Because the cognitive tests (ANAM) could not be administered in jails or prisons, only nonincarcerated
participants are included in this analysis. In addition, ANAM data were not
available for participants who: were interviewed by phone (n=4), declined to complete the
battery (n=1), or were legally blind (n=1); data could not be retrieved for two respondents
due to computer problems. Thus, of the original non-incarcerated surviving sample who
agreed to participate in the follow-up study (N=520), 78% have thus far completed ANAM
data and are included in this analysis.