Table 2: Summary of the findings from the selected studies ( ).

Reference number of the study/studiesType of TCComparison conditionFollowup lengthOutcome measures
RetentionSubstance useCriminal activityEmploymentHealthFamily and social relations

(1) Sacks et al., 2012 [19]PrisonTAU1 year+

(2) Zhang et al., 2011 [44]PrisonTAU1 year=
5 years=

(3) Messina et al., 2010 [45]PrisonOther TC1 year+====

(4) Welsh, 2007 [37]PrisonTAU2 years=++

(5) Sullivan et al., 2007 [46]PrisonTAU1 year++

(6) Morral et al., 2004 [47]PrisonTAU1 year=+=+

(7) Inciardi et al., 2004 [28]PrisonTAU6 months+++
1 year++
3 years+=
3 years 6 months++
5 years++

(8) Prendergast et al., 2004 [33]PrisonTAU1 year++
2 years+
5 years==+==

(9) Greenwood et al., 2001 [25]Community-based Other TC6 months=+++
1 year==+
1 year 6 months=++

(10) Nemes et al., 1999 [42]Community-based Other TC1 year 6 months=+++

(11) De Leon et al., 2000 [24]Community-based TAU1 year+=+=
2 years+ =++ =+

(12) Nuttbrock et al., 1998 [38]Community-based TAU1 year++

(13) McCusker et al., 1997 [51]Community-based Other TC6 months==
1 year==+

(14) Hartmann et al., 1997 [43]PrisonTAU6 months=+

(15) Bale et al., 1984 [39] Community-based  TAU1 year++++
2 years++ (illicit)
− (alcohol)
++

(16) Coombs et al., 1981 [41]Community-based Other TC1 year=+

TC: Therapeutic Community, Other TC: Other TC modality, TAU: Treatment As Usual.