For example, an animal study showed that long-term administration of olanzapine may cause insulin resistance (IR), by significantly increasing levels of IL-1β, IL-6 and TNF-α (19), and a prospective study with 12-month follow-up found that schizophrenics with a higher baseline IL-6 level had an increased risk of subsequent MetS (20). This evidence concerns the gene IL6 and Insulin resistance.