Objectives - To present a comprehensive review of the studies assessing the frequency of PTSD in the general population, in clinical populations and among subjects at risk. Design - An extensive search was made using the Excerpta Medica Psychiatry CD-ROM 1980-1993 (October). Using post-traumatic stress disorder as a key word, a total of 1,057 papers published in this timespan were retrieved. A further search was made using the same key word with MEDLINE CD-ROM 1988-1993. A manual search was also performed for all issues of the Journal of Traumatic Stress. Results - A total of 135 studies meeting inclusion criteria were selected for this review. Almost two thirds (n = 86, 64%) of these studies were carried out in the United States; only 8 (6%) studies have been carried out in developed countries. The sample size ranges from a low of 11 subjects up to a high of 22,463 subjects. The mean sample size is 500 and the median is 108. In terms of assessment methods, in one third (n = 45, 33%) of the studies the investigators used a PTSD symptom checklist (either self- administered or administered by a clinician), based on DSM criteria, to generate a PTSD diagnosis. In more than in one third of the studies (n = 44, 33%) of the studies, a structured interview was administered (e.g., the DIS, the SCID, the SADS), while in the remaining surveys the diagnostic evaluation was based either on an un- structured clinical assessment or on the administration of other specific assessment instruments (e.g., M-PTSD, IES, SCL-90-R or others). In 77 studies (57%) the investigators based their assessment on DSM-III diagnostic criteria for PTSD, whereas in 55 studies (41 %) DSM-III-R criteria were employed. Prevalence rates are discussed separately for the different population groups. Conclusions - There has been a remarkable increase in the number and quality of epidemiological studies on PTSD over the past decade. A substantial amount of information is now available about the frequency of PTSD among different population groups and among at risk subjects, and about risk factors, common symptom patterns, and natural history of this disorder. However, a number of important limitations of these studies are to be noted and should be addressed by future research efforts.

Objective - After a review of recent developments in the economic evaluation of mental health care, the study described in this paper suggests a methodology for the measurement and evaluation of costs in the Italian psychiatric system. Method and results - To conduct such an evaluation it is necessary to identify all relevant services, collect data on patients' receipt or utilization of health services (direct costs) and other services and resources within the socio- economic system (indirect costs), and to attach monetary values for the costs. A detailed unit cost list (LICU) was constructed for facilities available at South-Verona Community Psychiatric Service (CPS), as well as in many other community-based psychiatric services in Italy. This list covers psychiatric services, other public and private health services, criminal justice services, voluntary organisations and self-help groups. The procedure for calculating costs in three of these facilities (hospital inpatient service, psychiatric outpatient service and rehabilitation groups) are described in this paper in detail. A new instrument (ICAP) was developed to collect the data required to calculate the costs of community care for individual patients. In order to check the applicability and comprehensibility of the instrument, and the time ne- eded for its administration, the ICAP was tested with five patients. Conclusions - It will be interesting to utilise ICAP and LICU in a larger sample. The methodology described here would provide the basis for epidemiologically-based studies, as well as exploration of the factors which predict cost differences (such as socio-demographic characteristics, diagnosis, psychiatric history, ecc). It is important to emphasise the insights for policy and practice which can flow for the merged examination of costs, needs and outcomes. This research is presently in progress in South-Verona.