The group therapy literature usually treats Cluster C personality disorders together, often including other personality disorder types as well (Budman et al. 1996). In general, group therapy has been found effective as a sole modality (Alden 1989; Budman et al. 1996), but it is also a major component in day-treatment programs (Krawitz 1997; Piper et al. 1993; Wilberg et al. 1998) and as an adjunct to outpatient individual therapy. Group therapy for Cluster C disorders is effective, with studies finding an average median effect size for active treatments across all measures of 0.9 at termination and 1.1 at follow-up (Alden 1989; Ball et al. 2000; Budman et al. 1996; Krawitz 1997). Improvement has been shown in general areas such as distress, depression, and global functioning, although some studies have shown improvement in disorder-specific symptoms such as shyness or social avoidance (Alden 1989). Recovery following group therapy as a sole modality is not common (Budman et al. 1996), but treatment durations greater than 12 months have rarely been studied.