Khat abuse as risk factor for development of psychotic symptoms in trauma patients : a feasibility study for further genetico-epidemiological studies in the GGFRC, ethiopia

Background The Jimma University in southwestern Ethiopia has a unique health and demographic surveillance system called „Gilgel Gibe Field Research Center” (GGFRC) with a catchment area of about 50.000 people. In this setting, we studied the effect of khat use as risk factor for the development and the stability of psychotic symptoms among young men in the community. Our aim was to validate pilot data by testing the hypothesis, whether objective biological data on khat abuse are related in a meaningful way to behavioral self-reports of study participants and psychiatric symptom presentation assessed by trained interviewers. We assumed that khat alkaloids in urine samples of respondents are related to a higher probability of psychotic symptom presentation, especially in the subgroup with high trauma load. Furthermore, we wanted to demonstrate the reliability and validity of research methods that are necessary for future genetic epidemiological studies, i.e. the validity and reliability of pharmacological screening tests as well as assessments performed by trained local interviewers. Methods In this prospective study, trained local interviewers screened a representative cohort of young men twice within a period of nine months (T1: dry season, N=852, T3: rainy season, N=693) to determine the presence and stability of distinct psychiatric symptoms (CIDI) and to assess traumatic experiences (LEC-5). As part of the screening, urine samples were collected and analyzed for khat alkaloids by immunoassay tests for amphetamine. In a clinical validation interview (T2, N=126) mental health specialist reassessed the psychiatric symptom presentation (BPRS) in a randomly selected subgroup of 126 individuals of those persons who had been screened at T1. The validation study took also urine of this subgroup in order to validate the urine screening by a more extensive analysis of khat alkaloids (HPLC). Results Our results on the association between biological objective data and information on psychiatric symptoms assessed by interviews were related in a meaningful way: The proportion of khat-related psychotic symptoms was highest among respondents with positive khat tests and with high trauma load. This tendency was strongest during rainy season (T3) where the market availability and the use of khat was higher (Chi2 = 14.800, df 1, p Discussion By showing these meaningful variations, this pilot study suggest that important theories on the development of psychosis can be further studied in epidemiological and longitudinal designs among khat users. Our project can be seen as a pilot and feasibility study to prepare a comprehensive population-based genetico-epidemiological study on various gene-environment interactions that should be carried out in the very next future. The infrastructure of GGFRC offers us a unique opportunity to build collectives of multiple-thousand people in a shortest period of time and to perform genetic studies as they have not yet been taken in Africa in this form so far. The population is ideally suited to study the impact of polygenic risk profiles of various psychiatric disorders on behavioral traits and their interaction with environment.