Wittoucket al. (2011) conducted a meta-analysis to evaluate the short-term andlong-term effect of grief prevention as well as treatment on individuals withcomplicated grief. They used two methods to gather articles they needed. Thefirst includes the electronic databases Web of Science (WOS) and PsycArticles,the second method is utilizing the relevant studies from the reference list.
The inclusion criteria are listed as following: 1) the study conducted RandomizedControlled Trial (RCT) and included a comparison group, 2) the participants ofthe intervention were adults who lost their significant others, 3) theassessments included pre-and post or follow-up evaluation, 4) the outcomevariable involved the complicated grief, 5) the study was published in peer-reviewedjournal, 6) the published year of the study was from 1990 to 2007. Theyexcluded case studies, treatments for diagnoses relevant to other loss, treatmentsfor children, teenagers, caregivers, people with intellectual disabilities or peoplewith pet loss, treatments for people with life-limiting diseases, and drugtherapy.