Esquirol, like Pinel, believed that the origin of mental illness could be found in the passions of the soul and was convinced that madness does not fully and irremediably affect a patient's reason.

In 1817, under the restored Bourbon monarchy, Esquirol initiated a course in maladies mentales in the makeshift quarters of the Salpêtrière dining hall.

In 1818 following these trips he wrote a short memoir presented to the minister of the interior and a more detailed description of his findings published in the Dictionnaire des sciences médicales.

This program consisted of four points: At the behest of the minister of internal affairs, Esquirol next undertook a nationwide survey, visiting all the institutions throughout France where mental patients were confined.

He became the main architect of the national law of 1838 that instituted departmental asylums for all needy French mental patients and that is still in force today.