Safety concerns following the use of ketamine as a potential antidepressant for adolescent rats of both sexes

While ketamine is already approved for treatment resistant depression in adult patients, its efficacy and safety profile for its use in adolescence still needs further investigations. Preclinical studies proved dose- and sex-dependent effects induced by ketamine during adolescence, but few studies have evaluated the short- and long-term safety profile of ketamine at the doses necessary to induce its antidepressant-like effects. The present study aimed at evaluating the antidepressant-like effects of ketamine (1, 5 or 10 mg/kg; vs. vehicle; 1 vs. 7 days) during adolescence in naive or early-life stressed (i.e., maternal deprivation) rats of both sexes in the forced-swim or novelty-suppressed feeding tests. Safety was evaluated by measuring the psychomotor- and reinforcing-like responses induced by adolescent ketamine. In addition, long-term safety was evaluated in adulthood at the level of cognitive performance, or addiction liability (induced by a challenge dose of ketamine in rats treated with adolescent ketamine). The main results reinforced the potential for ketamine as an antidepressant for adolescence, but at different dose ranges for each sex. However, some safety concerns emerged for adolescent female rats (i.e., signs of sensitization at the dose used as antidepressant) and adult male rats (i.e., addiction liability when re-exposed to ketamine in adulthood), suggesting the need for caution and further research before moving forward the use of ketamine as an antidepressant for adolescence.