Since 1980, the number of women incarcerated in U.S. prisons and jails has increased by more than 750%, outpacing the increase in male incarceration by more than 50% [1, 2]. To address this, mandated residential substance use disorder (SUD) treatment, as an external motivator, has become a commonly used treatment engagement strategy in lieu of prosecution by the criminal justice (CJ) and child protective services (CPS) systems [3, 4]. Although there is some debate about the relative value of external motivation for increasing SUD treatment retention [5, 6], current evidence shows CJ-mandated treatment, as an external motivator, results in improved treatment retention as compared to nonmandated SUD treatment [7, 8]. Completing a full treatment program is vital, yet retention in residential SUD treatment is one of the major challenges for women . Further, relatively few studies have investigated the effectiveness of CPS-mandated treatment on increasing women’s residential SUD treatment retention, particularly compared to CJ- and nonmandated residential treatment [10–12].
Historically, court mandated SUD treatment research has focused largely on male or mixed-sex samples . For instance, Wilson et al.  conducted a systematic review examining 55 independent drug court comparisons and revealed that 80% (N = 44) featured largely male samples (60–90% male), and only one study (2%) had an all-female sample. As of late, the importance of examining sex-specific (women only) SUD treatment retention and completion outcomes is increasingly being recognized.
Women entering SUD treatment through the CPS and CJ systems generally have more severe SUDs than their male counterparts . Further, in contrast to women entering mixed-sex residential SUD treatment, those entering women’s SUD treatment are more likely to have more extensive histories of substance use . CPS- and CJ-mandated residential SUD treatment is a critical intervention for women, although challenges remain regarding this group’s vulnerability to treatment dropout. Challenges associated with increasing susceptibility to treatment dropout include having a co-occurring mental health disorder , increased stress [17, 18], and histories of physical and sexual abuse trauma . A large body of research on SUD treatment recognizes women who remain in treatment longer generally have improved treatment recovery outcomes, such as (a) reduction in substance use and long-term abstinence, (b) improved mental health conditions , and (c) increased family reunification rates . These findings call attention to the need to examine treatment retention differences in a sociodemographic diverse group of women mandated (CPS and CJ) or nonmandated into women’s residential SUD treatment.
CJ-mandated residential SUD treatment is generally an accepted predictor of increased treatment retention and completion rates [7, 8]. For instance, a large statewide study evaluating drug court programs in California revealed that the drug court model produced higher rates of SUD treatment completion and reduced recidivism as compared to a nondrug court model . However, because women may contend with different mandating systems to address their SUD, understanding the variability in treatment retention among different referral statuses may inform targeted approaches that improve women’s residential SUD treatment retention.
These separate referral sources function as three distinct external motivational conditions that may contribute to different residential treatment retention outcomes . For example, women mandated by the CPS system are required to complete treatment to retain or regain child custodial rights, and noncompletion of treatment may result in lost custody of children. Women who are mandated by the CJ system are required to complete SUD treatment in lieu of criminal prosecution, and completing treatment can lead to criminal charges being dropped or reduced. Alternatively, women who are nonmandated may not have the same weight of external pressure attached as with legal and CPS mandates; however, external motivation often comes in the form of family, significant other, or employer pressures to enter SUD treatment . It is important to note that women mandated into treatment by the CJ system, due to overriding jurisdiction, may also have child custody cases, increasing external motivation to engage in and complete treatment, whereas those who are CPS-mandated or nonmandated may not contend with this same risk of “double jeopardy” . Nevertheless, prior research has not adequately investigated the effects of CPS-mandated residential SUD treatment retention in comparison to CJ-mandated and nonmandated treatment [10, 12, 13].
Despite increased research interest on the role of court- or legally mandated SUD treatment in treatment retention, little is known about the effects of CPS-mandated in comparison to CJ- and nonmandated SUD treatment retention. A comprehensive review of the literature revealed few studies examining CPS-mandated treatment retention and completion outcomes compared to nonmandated women [12, 13]. For instance, participants in family dependency court (a CPS mandating agency) completed treatment at rates 20 to 30 percentage points higher than that of other parents not mandated by family dependency court, while remaining in SUD treatment longer .
Because prior work examining mandated SUD treatment retention has primarily focused on CJ-mandated treatment [10, 13], it is not known if CPS-mandated treatment, as an external motivator, results in improved treatment retention in comparison to CJ- and nonmandated women’s residential SUD treatment. With the continuing expansion of family drug courts (CPS mandating agency) in the United States from two in 1994 to 495 in 2018, this is particularly relevant . Nevertheless, no known studies have examined CPS-mandated women’s SUD residential treatment retention outcomes in comparison to CJ-mandated and nonmandated treatment [10, 12]. Because women enter women’s residential SUD treatment through coercively distinct pathways (CPS, CJ, or nonmandated), it is critical to understand the treatment retention differences among these groups to provide more effective treatment.
Moreover, among women who enter residential SUD treatment, the evidence is not clear whether having a co-occurring mental health disorder is a predictor of decreased treatment retention [16, 24]. Research that has examined associations between co-occurring mental health and SUD treatment has often found that having a mental health disorder is associated with lower treatment retention and poorer outcomes [16, 25]. However, the impact of co-occurring mental health disorders on SUD treatment retention may not always be uniform, varying by treatment modality, psychiatric diagnosis, and sex [16, 24–26]. For example, Choi et al.  found women with a co-occurring disorder were more likely to stay longer in treatment when compared to men with a co-occurring disorder. In contrast, prior work has shown women with co-occurring disorders in general have poorer SUD treatment retention than women without a co-occurring disorder . Advancing the current literature, a better understanding of whether having a co-occurring mental health disorder affects SUD treatment retention among mandated (CPS and CJ) or nonmandated women may have implications for women’s SUD treatment, particularly given the distinct coercive pressures associated with the three respective referral conditions.
To gain a fuller understanding and address the aforementioned limitations, this study examined specific psychological characteristics and whether having a co-occurring mental health disorder are contributors to SUD treatment retention among women mandated and nonmandated into residential treatment. These psychological characteristics include increased levels of stress [17, 28], depression , posttraumatic stress disorder (PTSD) , and anxiety [31, 32]. However, few studies have examined if known psychological contributors (i.e., PTSD, stress, depression, and anxiety) affected treatment retention between mandated and nonmandated referral statuses. Therefore, the current study sought to address each of these gaps by comparing samples of women mandated (CPS and CJ) or nonmandated into women’s residential SUD treatment to determine whether having a co-occurring mental health disorder or certain psychological characteristics affected number of days retained in treatment.
1.2. Study summary and hypotheses
Guided by prior empirical research, the primary purpose of this study was to examine differences in women’s residential SUD treatment retention (as measured by number of days in treatment) by referral status (CJ, CPS, and nonmandated). This study generated important insights for understanding retention differences among women entering residential SUD treatment via three primary treatment entry pathways. Moreover, understanding the effects on retention from having a co-occurring mental health disorder and certain psychological characteristics (PTSD, depression, stress, and anxiety) may aid treatment planning that mitigates early treatment dropout. Hypothesis 1 posits that women mandated by the CPS or CJ system into residential SUD treatment will be associated with more days retained in treatment compared to those nonmandated. Hypothesis 2 posits that women mandated into residential SUD treatment, in general, will be associated with more days retained in treatment compared to those who were nonmandated to treatment. Hypothesis 3 posits that women mandated by the CJ system into residential SUD treatment will be associated with more days retained in treatment compared to those mandated by the CPS system. Further, Hypothesis 4 posits certain psychological characteristics (increased stress, PTSD, anxiety, and depression symptomology) and having an additional mental health diagnosis will be associated with fewer days retained in treatment.