Ten controlled trials (n=4,457) were included. The authors stated that although three of these were randomised controlled trials (RCTs), two were analysed as quasi-experimental studies because of methodological issues identified in the review. The other studies were described as quasi-experimental.
Methodological limitations of the studies included high rejection rates of referred people, high rates of attrition often due to self-selection, treatment groups not comparable at baseline, small sample sizes, samples not representative and poor definition of interventions.
Short-term residential programmes (5 studies).
One study reported that an integrated mental health and abuse programme was associated with higher rates of programme completion than a substance abuse programme, but reported no difference between treatments in substance abuse.
One study reported that an integrated lower-demand rehabilitation programme was associated with higher rates of programme retention and housing and lower rates of substance abuse relapse than a higher-demand therapeutic programme. One study reported that an integrated residential programme was associated with higher retention rates at 3 months than an out-patient programme. The retention rates were low in both treatment groups (24% versus 8%). There were no reported differences between treatment groups in terms of housing and substance abuse outcomes. One study reported that eight residential programmes classified as having a 'good dual diagnosis treatment climate'(analysed together) were associated with higher levels of coping and abstinence than seven residential programmes not classified as having a 'good dual treatment climate'. One study reported that dual and primary substance abuse programmes were associated with the same low rates of 'successful discharges'.
Long-term residential programmes (5 studies).
One study reported that a low-demand integrated dual treatment residential programme was associated with increased rates of retention at 2 months, 'successful discharge' and abstinence, compared with two modified therapeutic communities. One study (RCT) reported that a low-demand dual treatment community residential programme was associated with increased rates of retention when compared with a dual treatment modified therapeutic community, but there were no treatment differences in substance abuse outcomes. Both programmes rejected many referred people.
One study reported that a low-demand therapeutic community was associated with increased rates of retention at 1 year and improved outcomes (less substance abuse, criminal activity, lower HIV risk behaviour and higher employment) at 1 and 2 years compared with a high-demand therapeutic community. Both therapeutic community treatment programmes improved outcomes in comparison with usual out-patient treatment.
One study in incarcerated people reported no difference between a dual treatment programme and a therapeutic programme in re-incarceration rates or substance-related crime 1 year after release. Participation in a modified therapeutic community after release was associated with less re-incarceration, less criminal activity and less substance abuse-related criminal activity than non-participation. One study reported that a long-term integrated residential programme(unlimited length of stay) was associated with increased rates of treatment retention at 3 months and increased rates of abstinence, and reduced homelessness at 6 months compared with a short-term (intended stay 3 months) integrated programme.