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THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE
Vol. 30, No. 3, pp. 537–550, 2004
Effectiveness of Long-Term Residential Substance
Abuse Treatment for Women: Findings from
Three National Studies#
Lawrence Greenfield, Ph.D.,1,* Kenneth Burgdorf,1
Xiaowu Chen,1 Allan Porowski,1 Tracy Roberts,1
and James Herrell2
1
2
Caliber Associates, Fairfax, Virginia, USA
Center for Substance Abuse Treatment, Rockwall II,
Rockville, Maryland, USA
ABSTRACT
The effectiveness of residential substance abuse treatment for women
was examined using data from the Center for Substance Abuse
Treatment’s Residential Women and Children/Pregnant and Postpartum
Women (RWC/PPW) Cross-Site Study and two other recent national
#
This study was supported under contract 270-97-7030 from the Center for Substance
Abuse Treatment (CSAT), Substance Abuse and Mental Health Services Administration (SAMHSA), and the U.S. Department of Health and Human Services (DHHS).
Views and opinions are those of the authors and do not necessarily reflect those of
CSAT, SAMHSA, or DHHS.
*Correspondence: Lawrence Greenfield, Ph.D., 11123 Midvale Rd., Kensington,
MD 20895, USA; E-mail: [email protected].
537
DOI: 10.1081/ADA-200032290
Copyright D 2004 by Marcel Dekker, Inc.
0095-2990 (Print); 1097-9891 (Online)
www.dekker.com
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Greenfield et al.
studies. Treatment success was defined as posttreatment abstinence from
further drug or alcohol use, measured through in-person follow-up
interviews conducted 6 – 12 months after each client’s discharge. Despite
differences in treatment programs, client profiles, follow-up intervals,
data collection methods, and other factors, all three studies found high
treatment success rates—ranging narrowly from 68% to 71% abstinent—
among women who spent six months or more in treatment. Success rates
were lower, and between-study differences were larger, for clients with
shorter stays in treatment. Controlling for salient client and treatment
project characteristics, strong associations between length of stay in
treatment and posttreatment abstinence rate were found in all three
studies, suggesting that women’s length of stay in residential treatment
is a major determinant of treatment effectiveness. In further analysis
of RWC/PPW data, treatment completion was also found to be an important outcome factor. Among clients who remained in treatment for at
least three months, those who achieved their treatment goals in three to
five months abstinence outcomes were as good as those for clients who
took more than six months to complete their treatment (76% – 78%
abstinent) and substantially better than those for clients who did not
complete treatment (51% – 52% abstinent). Notably, however, most of
the RWC/PPW clients who successfully completed treatment (71%)
required six months or more to do so.
Key Words:
abstinence.
Residential substance abuse treatment; Posttreatment
INTRODUCTION
In fiscal years 1993 –95, the Center for Substance Abuse Treatment
(CSAT) awarded 50 demonstration grants under its Residential Women and
Children (RWC) and Pregnant and Postpartum Women (PPW) programs.
The grants provided funding support for the development and operation
of comprehensive, long-term residential (LTR) treatment programs for
pregnant and parenting women with severe substance abuse problems,
including on-site care for clients’ infants and young children. In large part,
these programs were intended to stimulate increases in the numbers of LTR
treatment slots available to this important but underserved segment of the
population (1).
Although there was a growing body of literature on treatment
approaches for addressing the complex needs of pregnant and parenting
women with substance abuse problems (2), little data were available on the
effectiveness of LTR treatment for women at the time the RWC/PPW
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Residential Substance Abuse Treatment
539
program was initiated. Accordingly, a CSAT-funded cross-site study was
begun in 1996 to collect client outcome and other evaluation data for these
programs. The study design included plans for collection of information
about client posttreatment functioning using follow-up interviews conducted
six months after each client’s discharge. Among other information about
clients’ posttreatment lives, these follow-up interviews collected relapse
information about clients’ postdischarge alcohol and drug use, an outcome
dimension of particular interest. In the present analysis, any posttreatment
use of alcohol or illegal drugs is classified as relapse.
This paper compares RWC/PPW outcome findings to similar findings
from two other recent national studies that were conducted at about the
same time: CSAT’s National Treatment Improvement Evaluation Study
(NTIES) (3 –5), and the National Institute on Drug Abuse’s Drug Abuse
Treatment Outcomes Study (DATOS) (6 – 9). Both of these latter studies
sought broad representation of diverse forms of substance-abuse treatment
for both male and female clients. Both included subsamples of women in
LTR, which are the focus of the present analysis.
An issue of particular interest in this analysis is the relationship
between clients’ length of stay (LOS) in treatment and their posttreatment
success in maintaining alcohol and drug abstinence. Treatment LOS is a
major determinant of treatment cost in residential settings. With growing
concerns about treatment cost containment (10), LTR programs structured
to provide unusually long LOS are facing growing pressures to demonstrate
that the added cost of such treatment produces added benefits in terms of
improved client outcomes.
Much previous LTR research has demonstrated that clients with
moderate LOS tend to have more favorable outcomes than clients with
shorter LOS (8,9,11,12). Similar findings were reported specifically for
women LTR clients in the DATOS database (7). In most of these previous
analyses, however, the long-stay group has been defined as clients receiving
three or more months of treatment. The present study will extend previous
analyses to look at longer stays. The RWC/PPW program was designed
to support LTR projects with planned LOS of 6 – 12 months, and many
RWC/PPW clients actually received six or more months of treatment. The
DATOS and NTIES databases also contained significant representation of
clients with LOS of six months or more, permitting cross-study
comparisons of outcomes for clients with such extended periods of care.
In addition to LOS, treatment completion has been identified as an
important predictor of posttreatment abstinence in several LTR studies
(13,14). Interconnections between LOS and completion were also examined
in the present analysis.
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Greenfield et al.
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METHODS
This analysis focuses on women clients who received LTR SAT,
for whom post-discharge follow-up outcome data were available. The
RWC/PPW analysis sample is limited to the 32 (of 50) projects that were
able to provide adequate follow-up data, defined as completed interviews
with at least 50% of their former clients who were time-eligible for sixmonth follow-up within the cross-site study’s data collection window. The
respondent sample from these projects consists of 1154 women, who represent 75% of the projects’ time-eligible former clients. For DATOS and
NTIES, similar follow-up data are available for 219 and 424 LTR women,
respectively. All DATOS and NTIES findings reported here were extracted
from the studies’ public-use data files.
The RWC/PPW nonresponse analyses showed that follow-up response
rates were consistently higher for women with comparatively long periods
of stay in treatment than they were for women with shorter stays. To reduce
any resulting data bias, simple nonresponse adjustment weights were
developed for each project within four length of stay (LOS) groups (1 –
30 days, 31– 90 days, 91– 181 days, and 182 + days). In each LOS group,
the number of eligible clients was divided by the number of follow-up
respondents to calculate a nonresponse adjustment weight, which was
unitized (multiplied by the project’s overall response rate) and then was
applied to all respondents from that LOS group. All findings reported here
are weighted, using these adjustments.a Data needed for such adjustments
were not available for DATOS and NTIES; their data are unweighted.
In all three studies, post-discharge follow-up data were collected
primarily through in-person interviews with former LTR clients. In DATOS
and NTIES, these interviews were collected by national study staff; in
RWC/PPW, follow-up data were collected by local project staff or
evaluators and then were sent to the cross-site study for pooling and
analysis. Additional information about the three studies is presented in
Table 1.
The focal outcome variable in all three studies is post-discharge
abstinence from alcohol and drugs. In RWC/PPW and DATOS, abstinence
was defined as no use of any listed substance. In NTIES, a somewhat looser
definition was used: less than five post-discharge instances of use of any
listed substance. The intervals over which post-discharge behavior was
examined varied. The RWC/PPW follow-ups were conducted six months
a
These adjustments, while statistically desirable, actually had little effect. A second,
unweighted series of analyses produced results nearly identical to those reported here.
Residential Substance Abuse Treatment
Table 1.
541
Selected study characteristics.
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Study
Characteristic
RWC/PPW
NTIES
DATOS
Data collection period
No. LTR treatment sites
Follow-up client sample
Follow-up interval
(months after discharge)
Follow-up response rate
Definition of post-discharge
abstinence from
alcohol and drug use
1996 – 2001
32
1,154
6
1992 – 1995
13+
424
Varies
(mean = 10)
82%
< 5 times
per substance
1991 – 1993
32
219
6 and 12
75%
No use
63%
No use
after client discharge. The DATOS follow-ups were conducted 12 months
after client discharge, but they included questions about how long after
discharge any reported relapse first occurred. This made it possible to create
a six-month abstinence classification for DATOS, to supplement the
standard 12-month abstinence data. In NTIES, follow-up intervals varied
from 129 to 486 days after discharge, averaging 318 days, about 10 months.
The RWC/PPW database included project-provided classifications of
whether or not each client had satisfactorily completed her treatment plan
by the time she was discharged. Comparable data are not available from
the other two studies, so analyses of completion status are limited to the
RWC/PPW study.
RESULTS
Client Characteristics and LOS Distributions
Table 2 profiles the characteristics of clients in the three studies’
samples. Chi square (df = 2) was used to test the overall significance of
differences among the three studies on categorical variables, and Dunnett
multiple comparison test between proportions (15) was used for pair-wise
comparisons between RWC/PPW and the each of other two studies
whenever the overall three-group comparison was significant. For age, the
only continuous variable examined, analysis of variance (ANOVA) was
used to test for overall differences, and Dunnett multiple comparison test
between means (15) was used for pair-wise comparisons.
542
Greenfield et al.
Table 2.
Characteristics of women at treatment admission, by study.
Study
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Characteristic
Sample n
Primary substance/
reason for Tx
Cocaine/crack
Alcohol
Heroin
Marijuana
Methamphetamine
Prior substance
abuse treatment
Race/ethnicity
White
African American
Hispanic
Other
High school
diploma/GED
Currently working
Court supervised/
trial pending
Parent of minor
child/pregnant
Mean age [SD]
RWC
1154%
DATOS
219%
NTIES
424%
Chi-square
(df = 2)
52
14
8
5
13
84
72^^
8^^
11
1^^
3^^
66^^
80^^a,b
7^^a
8b
2^^
4^^
61^^
112.69**
19.64**
2.03
12.81**
42.7**
107.01**
32
40
15
13
47
28
57^^
11
4^^
53
13^^
72^^
12
2^^
46
56.75**
136.89**
0.17
42.82**
0.21
8
48
3^^
33^^
6^^
55^^
10.2**
36.48**
99
76^^
74^^
275.86**
30.3 [6.1]
29.8 [5.9]
31.4 [7.3]^^
5.96**c
Note: *p < .05, **p < .01 in overall three-group comparison; ^p < .05, ^^p < .01 in
paired-comparison with RWC/PPW.
a
Clients reporting both cocaine/crack and alcohol were included under ‘‘Cocaine/
Crack.’’
b
Clients reporting both cocaine/crack and heroin were included under ‘‘Heroin.’’
c
Result based on one-way ANOVA.
Table 2 shows many statistically significant differences among the
three studies’ samples. The overall impression, however, is of considerable
similarity among the samples. In all three samples, cocaine was the modal
presenting problem; African Americans were the modal race/ethnicity
group; about half the clients had high school diplomas or GEDs; less than
10% were employed just prior to admission; and the average age at
admission was about 30. Further, majorities of all three studies’ clients
reported prior SAT, before the current episode. Nearly all of the RWC/PPW
Residential Substance Abuse Treatment
543
Table 3. Client length of stay (LOS) distribution, by study.
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Study
LOS (days)
RWC
DATOS
NTIES
Chi-square
Sample n
1 – 30
31 – 90
91 – 181
182 +
Total*
1154%
21
20
21
37a
100
219%
15
19
27
38
100
424%
40^^
24
24
12^^
100
(df = 2)
75.52**
0.15
0.14
101.41**
^p < .05, ^^p < .01 in paired-comparison with RWC/PPW.
*p < .01, **p < .05 in 3-group comparison.
a
Differences from 100% in summing column percentages are due to rounding.
clients were pregnant or parenting at treatment admission, as were about
three fourths of the women in both DATOS and NTIES.
Table 3 describes the three studies’ client LOS distributions. As shown,
the RWC/PPW and DATOS distributions were similar. As compared to
these studies, NTIES projects had comparatively few long-stay clients with
LOS > 181 days (12%, vs. 37% – 38%) and comparatively large numbers of
short-stay clients with LOS of 1 –30 days (40% vs. 15% – 21%).
LOS and Post-Discharge Abstinence
The overall percentages of former LTR clients from the three studies
who reported no drug or alcohol use from discharge to the follow-up
interview were: RWC/PPW (60%), six-month DATOS (51%), 12-month
DATOS (46%), and NTIES (40%). Given the large LOS differences
between NTIES and the other two studies, along with the many
methodological differences among the three studies, the meaning of these
varying overall rates is not immediately apparent.
Figure 1 displays the four sets of client abstinence data, broken out by
LOS group. In all four data sets, post-discharge abstinence rates increased
markedly with increasing LOS. Between-study differences were largest for
short-stay clients but converged as LOS increased. For clients who received
six months or more (182 + days) of treatment, post-discharge abstinence
rates were high in all four data sets, ranging narrowly from 68% –71%. For
shorter LOS conditions, RWC/PPW clients consistently showed significantly higher abstinence rates than clients from treatment sites represented
in the other two studies.
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Greenfield et al.
Figure 1. Percentage of abstinent post-discharge by LOS and study. Note:
**Difference from RWC is statistically significant at p < .01.
A client’s LOS in treatment is partly influenced by the practices and
policies of the treatment facility, which may limit how long clients are
allowed to remain in a program. Insurance coverage may also be a limiting
factor in some cases. Beyond such external constraints, self-selection may
also be important. If clients with certain characteristics systematically
remain longer in treatment than do other clients, it may be these other
Residential Substance Abuse Treatment
545
Table 4. Logistic regression odds ratios (OR) obtained in predicting abstinence,
by study.
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DATOS
Variables in model
RWC
6-Month
12-Month
NTIES
n
Age
H.S. diploma/GED
Employed FT/PT
Prior SA treatment
Cocaine/crack is primary
Heroin is primary
Methamphetamine is primary
Marijuana is primary
Alcohol is primary
Another drug is primary
Hispanic
White
African American
Court supervised
Parent/pregnant
LOS groups
31 – 90 days
91 – 181 days
182 days or more
1154
1.03*
NS
NS
0.64*
0.02*
NS
NS
NS
0.58**
NS
NS
NS
1.42*
NS
NA
219
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
2.04*
NS
NS
219
NS
NS
NS
.42**
NS
NS
NS
NS
.24*
NS
NS
NS
2.24*
NS
NS
424
1.04*
NS
NS
.58*
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
1.3
2.06**
3.06**
3.55*
3.36*
10.0**
2.90
4.07*
12.89**
1.44
4.29**
6.44**
Notes: NA = Not applicable; NS = Not selected.
*p < .05.
**p < .01.
characteristics—rather than LOS—that are causally responsible for a
statistical association between LOS and treatment outcome. To examine
this possibility, we conducted a series of logistic regression analyses. We
examined the association between treatment LOS and post-discharge
abstinence, separately for each of the four data sets, controlling for a
common series of client characteristics that were available in all of the data
sets. Results of these analyses are summarized in Table 4.
Table 4 shows that LOS was the only predictor variable that was
significantly associated with treatment outcome (post-discharge abstinence)
in all four data sets, and it was the single strongest predictor in each one. In
all four data sets, controlling for other salient client characteristics, the odds
of remaining drug-abstinent throughout the follow-up period were
significantly greater for clients who received 91 –181 days of treatment
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Greenfield et al.
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and those who received 182+ days of treatment than they were for those in
the reference group of clients who received 1 – 30 days of treatment.
Treatment Completion, LOS, and
Post-Discharge Abstinence
In a further analysis of RWC/PPW data, we added treatment
completion status as another predictor variable in the logistic regression
analysis described in Table 4. We combined the 1– 30 day and 31 –90 day
LOS groups in this analysis, since there were no completers in the 1– 30 day
group. The modified analysis produced a significant interaction effect
between LOS and completion, where the odds ratios (ORs) for abstinence
were over three times greater for completers than they were for
noncompleters at both the 91 –181 day and 182+ day LOS groups (both
at p < .001), but the difference between completers and noncompleters was
not significant for the 1 – 90 day LOS group.
The interaction is shown graphically in Fig. 2. Clients who did not
complete treatment had comparatively poor posttreatment abstinence rates
(46 –52%) no matter how long they stayed in treatment; clients who left
treatment within the first three months and were described as having
completed treatment had slightly (not significantly) better outcomes than
noncompleters (59% abstinent); clients who completed treatment within
three to five months had a very high success rate (78% abstinent), as high
Figure 2. Percentage of RWC clients abstinent post-discharge by LOS and
completion. Note: n per cell shown in parentheses.
Residential Substance Abuse Treatment
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as that for clients who stayed more than six months and completed
treatment (76% abstinent). However, in RWC/PPW projects, the great
majority of clients who completed their treatment plans took more than six
months to do so (71%).
DISCUSSION
One apparent implication of the findings from this analysis is that
quantitative answers to the question of the effectiveness of long-term
residential substance abuse treatment for women hinge substantially on
what is meant by long-term. For women who received six months or more
of LTR, the three national studies—and four data sets, collectively
representing over 75 treatment sites—showed remarkably convergent
findings. Despite data set differences in treatment programs, client
characteristics, follow-up intervals, data collection procedures, and other
factors, all four data sets showed 68% – 71% of clients who received
more than six months of treatment reported no drug or alcohol use since
leaving treatment.
For women who received shorter treatment episodes, the four data sets
were also consistent in that all showed progressively declining abstinence
rates as LOS decreased, though the steepness of the decline varied from
study to study. The quantitative outcome difference between long and short
stays was greatest in DATOS, where six-month post-discharge drug/alcohol
abstinence rates ranged from 71% for clients with more than six months in
treatment down to 21% for clients with 1 – 30 days of residential treatment.
The NTIES showed a similarly low post-discharge abstinence rate for
clients in the 1– 30 day group: 25%. The RWC/PPW showed significantly
higher post-discharge abstinence rates (at 43% or above) than two or more
of the other three data sets for clients in all three LOS groups in the 1– 181
day range. The reasons for these differences are not known. Given the
many methodological and other differences among the four data sets, there
are many possible explanations.
One obvious possibility is that between-study outcome differences for
comparatively short-stay clients may be due to differences between the
treatment programs represented in RWC/PPW and those studied in NTIES
and DATOS. Unlike projects in the other two studies, the RWC/PPW
projects were homogeneous in that, as a condition of their CSAT funding
grants, all provided comprehensive, gender-specific services, including onsite care of clients’ infants and young children. Also, RWC/PPW projects’
diagnostic and clinical services tend to be most intensive during the first
weeks of treatment, and clients who leave these projects early are
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Greenfield et al.
frequently referred to other treatment providers for continuing care.
Possibly, some combination of these distinctive programmatic features
accounts for the comparatively high post-discharge abstinence rates for
short-stay RWC/PPW clients. If such program differences are responsible
for the between-study outcome differences for short-stay clients, however, it
would appear that these influences become progressively less salient over
time, since clients who persisted in treatment for six months or more
evidenced similarly favorable outcomes in all three studies.
An interesting methodological finding is that, within the 6 –12 month
follow-up range represented here, follow-up interval does not appear to be
an important factor influencing measured post-discharge abstinence rate.
This is particularly clear in DATOS, where there is only a three-point falloff between the six-month abstinence rate for clients in the long-stay group
(71%) and the 12-month abstinence rate for that same group (68%). The
same is true for the 1 – 30 day group, where the 6- and 12-month abstinence
rates are 21% and 18%, respectively. In that study, most of the clients who
relapsed at some time within 12 months of discharge reportedly did so
within the first six months.
These comparative findings from NTIES and DATOS generally
increase our confidence in the outcome findings from the RWC/PPW
cross-site study. Previous studies on the effectiveness of substance abuse
treatment have often reported lower rates of post-discharge alcohol and
drug abstinence than we found for RWC/PPW. Also, the conventional
wisdom that drug and alcohol abuse are chronic recurring disorders, for
which relapse is a common and expected manifestation of the disease,
suggests that one should not expect to find high rates of persistent
abstinence from alcohol and drugs after discharge from any treatment
program. These considerations led us to question whether the RWC/PPW
outcome findings were consistent with other findings for similar client
groups in similar kinds of treatment and, if not, whether there was some
problem with the way RWC/PPW data were collected. Perhaps the followup interval was too short?
The other two large national studies of treatment outcomes have proven
to be confirmatory on both of these points. As compared to findings from
NTIES and DATOS for similar clients (i.e., adult women, most of whom
were pregnant or parenting at treatment entry) in similar forms of treatment (i.e., LTR), the RWC/PPW outcome findings are not especially unusual (particularly for clients in the long-stay group), and the study’s
follow-up interval does not appear to have been a problem. Buttressed by
the cross-validation these other studies provide, we are inclined to take
the RWC/PPW outcome findings at face value and conclude that, given
sufficient time, long-term residential substance abuse treatment for pregnant
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Residential Substance Abuse Treatment
549
and parenting women often is effective in assisting clients to achieve lasting
abstinence from further drug or alcohol use.
Our analysis also suggests that it is not time, per se, that causes
treatment to be successful. Among clients who remain in treatment for
some minimal period (perhaps three months, in the RWC/PPW case), doing
the work needed to complete one’s treatment goals may be the key to posttreatment success in remaining drug abstinent. In RWC/PPW, clients who
failed to complete their treatment plans had comparatively poor outcomes,
no matter how long they spent in treatment. Conversely, clients who
completed treatment within 91 – 181 days had a very high abstinence rate,
as high as the one for clients who required six months or more to complete
their treatment. These mid-LOS success stories were comparatively rare;
however; most RWC/PPW clients who successfully completed treatment
(71%) required six months or more to do so.
These findings, while highly encouraging, raise several other questions
that will require further research. First, how long-lasting are the benefits of
LTR for adult women: how well do the abstinence rates found in these
three studies over 6 –12 month follow-up periods hold up over longer
periods: and what factors affect any later fall-off in post-discharge
abstinence that is observed in this client population? Second, what are
the cost implications of providing truly long-term residential treatment (i.e.,
treatment of six months or more in duration) for adult women: are the
incremental benefits of unusually long treatment great enough to justify the
additional cost? Third, to what extent are the favorable outcomes that these
studies found for adult women replicable for other groups: given
comparable LOS, would adult men and/or teenagers respond similarly well
to similarly tailored opportunities for extended residential treatment?
ACKNOWLEDGMENT
This research was funded under CSAT contract 270-97-7030.
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