“…All studies were conducted in high-income countries, with seven in the USA [15,23,[41][42][43][44][45], one in Canada [46], one in Israel [47] and one in the UK [20]. Seven papers sampled only military veterans [15,23,41,42,44,45,47], two papers sampled only active-duty military personnel [43,46] and one sampled both active-duty and ex-service personnel [20].…”