Depressive syndromes have profound and complex causes, which cannot be reduced to single biological or biochemical mechanisms, but the insufficient activity of monoaminergic neurotransmitters is certainly implicated [105,106,107], as are neuroendocrine axis imbalances (CRH-ACTH-corticosteroids) closely connected to the GABAergic system [108,109,110,111,112] and the consequent different functionality of specific brain areas that regulate sleep, appetite, sexual desire and mood. The gene discussed is POMC; the disease is depressive disorder.