Exploring the association between khat use and psychiatric symptoms: a systematic review

Objectives Consumption of the drug khat is high across East Africa and the South-Western Arabian Peninsula despite evidence for its adverse psychiatric effects. This systematic review aims to explore cross-sectional research in the field to determine the strength of the association between khat use and psychiatric symptoms Methods Six databases were searched in October 2021 - Ovid Medline, Embase, APA PsycINFO, CINAHL, Scopus and Proquest - using the following search terms: "khat"OR "qat"OR "qaad"OR "catha"OR "miraa"OR "mairungi"AND "depression"OR "anxiety"OR "mania"OR "psych∗"OR "schiz∗"OR "mental"OR "hallucinations"OR "delusions"OR "bipolar". Eligible studies were cross-sectional studies of any population or setting comparing the prevalence of psychiatric symptoms in long term or dependent khat users with non-users. The quality of each study was appraised by the Newcastle-Ottawa scale. A meta-analysis was planned using a random effects model to produce an OR with 95% CIs - using the Mantel-Haenszel method - alongside an I 2 statistic to represent heterogeneity. The quality of this meta-analysis was appraised using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) scoring system. Results 35 studies were eligible for inclusion (total participants=31 893), spanning 5 countries (Ethiopia, Somalia, Kenya, Saudi Arabia, UK). Meta-analysis suggests that khat use is associated with an 122% increased prevalence of psychiatric symptoms (OR 2.22, 95% CIs 1.76 to 2.79, p<0.00001, GRADE score: 'very low'). Conclusions The high heterogeneity of the meta-analysis is likely due to the wide variation between the studies within the evidence base. To perform a more accurate systematic review, further primary studies are needed with standardised measurements of variables, particularly khat consumption. PROSPERO registration number CRD42020224510.