Characteristics of the 31 studies included in the meta-analysis.

ALIC: Anterior limb of the internal capsule VC/VS: Anterior limb of the internal capsule–ventral capsule- and ventral striatum Response defined as a reduction of Y-BOCS scores > 35% * The authors make reference to four patients with severe OCD treated with DBS but information is provided just for one. a One patients included in Nuttin et al., 1999 [20] b Three patients included in Gabriels et al., 2003 [22] c Patient included in Aouizerate et al., 2004 [27] d One patient included in Aouizerate et al., 2004 [27] e Patients included in Guehl et al., 2008 [32] f Ten patients included in Greenberg et al., 2006 [12] and five patients included in Nuttin et al., 2003 [23] g Five patients included in Greenberg et al., 2010 [10] h Patient included in Goodman et al., 2010 [37] i Three patients included in Mallet et al., 2008 [33] j Two patients included in Mallet et al., 2008 [33] k Five patients included in Jimenez-Ponce et al., 2009 [35] l Information on long term response available for 3 patients m Individual data not available, results correspond to mean results from the study n Information available in 8 patients o Information available in 5 patients Characteristics of the 31 studies included in the meta-analysis.