Inhibitors of PDE (the most famous of this group being Viagra) can prolong or enhance the effects of physiological responses mediated by cAMP and cGMP by inhibition of their degradation by PDE and are considered potential therapeutics for pulmonary arterial hypertension, coronary heart disease, dementia, depression, and schizophrenia [37]. Here, ALDH7A1 is linked to depressive disorder.