The BRIGHT trial has several important findings. We show that providing group CBT for depression to clients with persistent depressive symptoms receiving residential substance abuse treatment is associated with better improvement in both depression and substance use outcomes. While all clients in our study, regardless of study condition, reduced their levels of depressive symptoms, intervention clients experienced greater decreases and their mental health functioning approached population norms. Among clients who had the opportunity for substance use at the 6-month post-baseline interview, intervention clients reduced their use by more than half compared to UC clients. It is notable that despite being a specific treatment for depression, the intervention was associated with clinically and statistically significant improvements in both mental health and substance use outcomes.
Few studies focus on the treatment of individuals with depression entering substance abuse treatment, and the majority of these examine pharmacotherapy.41
To our knowledge, this is the first large-scale trial of a psychosocial treatment for depression provided within standard substance abuse treatment, and adds to the small literature on effective treatments for individuals with co-occurring affective and substance use disorders. Apart from one study of interpersonal psychotherapy with 26 patients and another study of individual CBT with 35 patients, previous studies of psychosocial treatments have all included pharmacotherapy provided by a psychiatrist, a resource unavailable to most publicly funded substance abuse providers.42-45
While the CBT study found that individual CBT significantly lowered both drinking outcomes and depressive symptoms among alcoholics, the sample was less severely ill– e.g., baseline BDI-II was greater than or equal to 10, (versus 17) and only a single participant met criteria for major depression.42
Our findings extend these findings to include a group format, drug users in addition to alcoholics, and clients with severe depressive symptoms.
Our study addresses a critical need to develop and test integrated models of care suitable for the public-sector substance abuse treatment system. Lack of access to efficacious depression treatment for substance abusers is an important public health problem. Rates of current major depression are 2-4 times higher among substance abusers than in the general population,1, 46
affecting 15-35% of people seeking substance abuse treatment.47
Persons with co-morbid depression and substance use disorders experience greater impairment48
and worse outcomes than persons with only one of these disorders.49-51
Although current guidelines state that services for individuals with co-morbid substance use and mental disorders should be available regardless of setting, studies have shown that few public sector substance abuse treatment organizations are able to provide for the mental health needs of individuals with comorbid disorders.52, 53
Fewer than 9% of U.S. adults with a probable co-occurring disorder were able to access both mental health and substance abuse treatment.54
Public-sector programs typically do not provide mental health services because few substance abuse providers have qualified mental health professionals on staff,8, 55
and most do not have the funding mechanisms or resources to hire mental health professionals. In order to increase access and improve outcomes for individuals with comorbidity, interventions that use available resources need to be developed and evaluated. Because BRIGHT was implemented using typical substance abuse counselors, we address a critical limitation of the current system.8
A cost analysis will be reported elsewhere. The study demonstrates that it is possible to develop the capacity of substance abuse programs to deliver evidence-based mental health care by enhancing the skills and expanding the clinical roles of substance abuse counselors. If more broadly implemented, this approach could increase access to effective mental health care for the many individuals who enter the substance abuse treatment system with co-occurring persistent depressive symptoms. Moreover, because most substance abuse treatment occurs in a group format, our adaptation of group CBT for depression is consistent with providers’ expectations of what a usable treatment looks like.
Results from our study should be generalizable to the large population of individuals with persistent depressive symptoms entering residential treatment. Our study population included diverse cultures and ethnicities, and study sites were geographically spread across Los Angeles County. Participants were typical of clients enrolled in public-sector treatment, as most were single, unemployed, and indigent. To increase generalizability, we included clients with a range of severity and disorders, and had few exclusion criteria. About half had a current major depressive disorder. We also included individuals on medication as long as they continued to experience depressive symptoms. Given the difficulty of distinguishing between a substance-induced depressive disorder and an independent depressive disorder, initiating a treatment that is effective for both and which does not have the liability of medication side effects is advantageous.
The observed rates of CBT treatment attendance and completion in the absence of external incentives suggest that both clients and staff perceived the treatment to be acceptable and that the intervention is feasible. For example, we relied on the residential staff, who did not receive any training or exposure, to ensure that clients assigned to the BRIGHT condition received the intervention. In practice, this meant they had to remind clients, reschedule appointments, and ensure clients were on time. In addition, residential staff had to keep track of clients entering treatment in order to screen and enroll all eligible clients. Continued support for screening and client participation in the intervention was demonstrated by our low refusal rates and attendance in the intervention groups. Consistent with the improvement in outcomes, counselors without previous exposure to CBT for depression or to other depression treatments were able to deliver the treatment with acceptable levels of adherence and competence.
Our study has several limitations. Despite our efforts to develop and evaluate a treatment tied to the available resources of substance abuse providers, additional resources were required. Counselors went through significant training and weekly supervision by a PhD level psychotherapist, which may be more training and supervision than public programs can provide. BRIGHT was led by two counselors and the group size was limited to 10 which also increases the resources needed. We did not conduct a randomized trial, although our quasi-experimental study design, in which sites were assigned to alternate between the intervention and usual care conditions, minimized the chance of unmeasured site or subject characteristics influencing outcomes, and we did not observe differences by either site or intervention status. In the last year of the study we centralized the delivery of the intervention; clients were transported to a single site to receive the intervention. While this could have resulted in contamination, there were no differences in treatment attendance or outcomes associated with this change, and we continued to see a difference between our intervention and comparison conditions. We tested BRIGHT in a residential setting in which clients were expected to stay 3-6 months, and it is unknown whether the intervention will be feasible in 28-day programs or effective in outpatient settings. Small residential programs may not have sufficient clients to support a group. More work is needed to test the feasibility of BRIGHT in different settings.
We did not confirm self-report with urinalysis or a clinical interview and the lack of more thorough screening for co-morbid conditions is a limitation. Follow-up assessments were also unblinded to treatment allocation. Subjects may have under-reported their substance use or depression, although previous studies suggest the validity of self-reported mental health and substance abuse outcomes in similar populations, and the measures we used are based on previously-validated scales.21, 22, 56-59
We do not know whether the treatment influenced both depression and substance abuse directly, or whether the improvements in depression led to the improvements in substance use. This is an important area for further study. While all clients should have received the same amount of total residential treatment, it is probable that BRIGHT clients perceived themselves to be receiving increased clinical attention.
Taken together, our results provide support for a new model of integrated care suitable for substance abuse programs. Integration exists on a continuum, ranging from the co-location of mental health and substance abuse providers to integrated treatment teams staffed by experts in both disciplines. However co-location has not been shown to be effective,7
and integrated treatment teams are expensive to deliver and may not be cost-effective for individuals with less severe mental disorders. Future studies should include longer follow-up times and address the challenges of more broadly implementing this model of integrated care.