PMCH and Anxiety: Overall, the meta-analysis revealed that the deletion of MCH signaling suppressed non-REM sleep, anxiety, response to novelty, startle response, stress-induced hyperthermia, conditioned place preference, and olfaction (p<0.05) and that MCH signaling deficiency enhanced locomotor activity, wakefulness, alcohol preference, motor activation by psychostimulants, aggression, male sexual behavior, and social interaction (p<0.05).