The methodological quality of the studies varied but was selleck chem often rather poor due to high attrition rates, lack of objective verification of study findings, and a focus on one single study site (cf. Table 1). The oldest controlled studies date back to the beginning of the 1980s [39�C41]. The bulk of studies has been carried out/published in the 1990s. All controlled studies have been performed in the United States. Despite a growing research tradition in Europe, Australia, and South America, only observational uncontrolled studies have been carried out on these continents.The follow-up period in most controlled studies is between 6 and 24 months, and only three studies have followed participants for more than 36 months.

Study outcomes may vary according to the follow-up moment [24, 25, 33], but usually the magnitude of the difference(s) between the experimental and control group diminished over time (cf. Table 2). Overall, great within-group reductions in problem severity were observed between baseline and follow-up assessments, in particular regarding drug use, criminal involvement, and employment. The two outcome measures that were assessed in most studies are ��substance use�� and ��criminal involvement.�� All included studies reported at least one outcome measure in one of both categories. Eight out of 13 (note that this number is lower than 16, as not all studies reported outcomes concerning all categories) studies reported at least one positive significant difference between the TC and control group regarding legal outcomes at the one-year follow-up, while 9/14 studies found significantly better substance use outcomes among the TC group at that time (cf.

Table 2). All studies included multiple outcome indicators (also within one category), but only one study succeeded to find several significant, positive outcomes regarding most legal outcome measures (i.e., reincarceration rate, days to first illegal activity/incarceration, and length of prison sentence) [34]. Most studies found only one significant between group difference per category (e.g., time to drug relapse), while other outcome indicators within this category did not differ between groups (cf. Table 1). Significantly better outcomes in one category (e.g., substance use, criminal involvement) are not necessarily accompanied by improved outcomes on other domains (e.g., employment, psychological health). Only four studies found significant differences regarding three or more outcome categories [24, 32, 42, 43].3.1. Treatment Retention, Health, and Social FunctioningAs opposed to all other outcome categories, Anacetrapib TC participants scored worse in comparison with controls on treatment retention/completion.