[2] A few of his major contributions consisted of his work with delusions of persecutions, a concept coined "folie à deux," and his description of hysterical anorexia.

Recognizing his son's potential at an early age, he enrolled him at the Lycée Louis-le-Grand in Paris where Lasègue quickly distinguished himself among his peers.

He spoke fluent Latin, showed a great comprehension of the Greek language, and excelled in philosophy and rhetoric.

[5] Influenced by his friends and Falret, Lasègue enrolled in the Faculté de Médecine at the University of Paris in 1839 but it wasn't until he attended a lecture from Armand Trousseau at the Hôpital Necker that he decided to abandon his studies in philosophy and pursue an education in medicine with a particular interest in psychiatry.

Lasègue wrote articles about abnormal behaviour when common patterns were found in the standardized notes he would take of his cases.

[7] Lasègue was also a physician at Pitié-Salpêtrière Hospital and Hôtel Necker and was employed as Trousseau's Chef de Clinique from 1852 to 1854.

He gave multiple lectures on mental and nervous diseases throughout the 1860s and became professor of clinical medicine at the Hôtel Necker in 1867.

Due to his work on general paralysis, Lasègue was able to point out how varying determinants can manifest as the same symptom regardless being caused by brain disorders.

He disagreed with both the view of new wave neurologists and old school theorists; he divided persecutory delusions into two categories: general and partial, and argued that further divisions were not unnecessary.

Contrary to popular belief at the time, he believed that auditory hallucinations were not necessarily the cause or effect of persecutory delusions.

He firmly believed that in order to determine the cause of mental illnesses, it is crucial that a patient's history is recorded in detail.

This is because Lasègue focused on aspects revolving around psychological systems, such as the role of family interactions and parental attitudes.

[3] Despite this however, both Lasègue and Gull did not acknowledge the fear people have of weight gain and their overall body image which is actually classified as one of the diagnostic criteria today for anorexia nervosa.

However, Lasègue noted that he could tell malingerers apart from patients experiencing real sciatic pain by just conducting the leg raise test.

His daily work routine consisted of a great number of alcoholic patients whom he studied and accessed in police hospitals.

[20] Lasègue, alongside another physician named Alexis Charles Legroux, went on to establish a correlation between cases of scurvy in German prisons and the lack of physical activity relative to the duration of enclosure.