Relatively few pre-treatment interventions to increase out-patient mental health (MH) service use have been created and experimentally tested. Therefore, not only is there limited availability of these interventions, it is uncertain whether existing interventions are effective. Moreover, it is unclear which components of the interventions are effective. To address these gaps in knowledge, a systematic review of pre-treatment interventions was conducted, using the Cochrane Review methodology. Three primary outcomes were evaluated: attendance at any type of out-patient MH visit; number of appointments of any type of out-patient MH visit; and/or initiation and adherence to psychotropic medication. PubMed and PsycINFO databases were thoroughly searched for studies that met the inclusion criteria. A data extraction form was designed and employed to systematically extract data from all included studies. In the 15 included studies, 18 different active interventions were evaluated. The interventions ranged in duration of interaction from one mailed flyer to ten 90-minute psychoeducation sessions. Most studies (n = 11) included one intervention group, compared with one control, or usual care, group. The interventions were categorized by the type of barriers they aimed to address, resulting in six broad categories: MH knowledge; MH knowledge/attitudes; MH knowledge/attitudes/ logistical barriers; MH knowledge/family involvement; care management; and home visits. All included studies received a quality assessment rating of "good" or "fair." The main finding of this thesis is that all categories of interventions increased at least two of the three primary outcomes. The care management interventions measured and increased all three outcomes; these interventions also had some of the highest quality ratings. Therefore, care management interventions appear most effective at increasing out-patient MH service use. Implications for practice and research are discussed.