OBJECTIVES: Cost of mental illness studies are important in the decision making process for allocating resources or setting priorities for mental healthcare and prevention. Summary information regarding available cost-of-illness (COI) studies can help identify areas for future study to support decision making.  We performed a descriptive analysis of cost of mental illness studies, focusing on design characteristics and costs. METHODS: We identified all cost of mental illness (ICD10 diagnosis group: Mental and Behavioral Disorders) studies represented in a database of COI articles published between 2005 and 2014.  We examined information on study perspective, cost type (e.g., direct medical, direct non medical), data source, funding source, publication year, and geographic income region. We also reported the average patient cost by currency for recent publications (i.e., 2011 to 2014).  RESULTS: There were 84 articles included in the study.  The proportion of studies that reported 1) Patient/caregiver, 2) Societal, 3) Private payer or Public payer, 4) Other and 5) Not available perspectives were as follows: 3.6%, 62%, 6% or7%, 1% and 18%.  The proportion of studies that included direct medical cost, direct non-medical costs, indirect costs and intangible costs at all were as follows: 98%, 54%, 62%, 5%. The distribution in terms of geographic income region was as follows: 86% for high income region, 9.52% for middle income and 0% for low income region.  The top three categories for funding were: pharmaceutical companies (30%), government (27%), and unfunded (19%).  Among 38 articles published between 2011 and 2014, the average cost per patient was: 13,388.2 USD, 16,655.5 CAD and 31,213 EUR. CONCLUSIONS: The per patient cost of mental illness is substantial.  Cost of mental illness studies from the patient’s perspective and from low-income regions are needed to enrich our understanding of the burden of mental illness.