Inclusion Criteria:  FOR PATIENTS WITH RECURRENT DEPRESSION :  Patient who has provided oral consent Adult with moderate to severe depression according to DSM-5 criteria (Hamilton HDRS-17 score ≥ 18), with a number of depressive episodes ≥ 3  PATIENTS PRESENTING WITH A FIRST DEPRESSIVE EPISODE  Patient who has provided oral consent Adult with moderate to severe characterized depression according to DSM-5 criteria (Hamilton HDRS-17 scale score ≥ 18) presenting with a first depressive episode.  CONTROLS  Person who has provided oral consent Adult who has never shown signs of depression  Exclusion Criteria:  Person not affiliated with national health insurance Person subject to a measure of legal protection (curatorship, guardianship) Pregnant or breastfeeding women Adult unable to express consent Minors Person with a metabolic syndrome (according to NCEP/ATP-III criteria: 3 of the following 5 criteria: Waist circumference ≥ 102 cm in males and ≥ 88cm in females, Triglycerides > 1.50 g/L, HDL-Cholesterol < 0.40 g/L in H, HDL-Cholesterol < 0.50 g/L in F, Blood pressure ≥130/85mmHg, Fasting blood glucose ≥ 1.10 g/L), Person with type 1 or type 2 diabetes, Person with a mild depressive episode (HDRS-17<18), Person with concomitant antipsychotic treatment Person with bipolar disorder, Person with a moderate to severe alcohol use disorder according to DSM-5 criteria Person with schizophrenia, Person with a persistent delusional disorder, Person with an autism spectrum disorder.