A non interventional study to Investigating the ratio of Mis-diagnosed bipolar symptoms in Patient with Major Depressive Disorder (MDD) - Improve

The study will only detect hypomanic symptoms in treatment resistant MDD patients by mean of HCL-32 administration. Further re-evaluation of MDD diagnosis is not a direct aim of the study. No efficacy and tolerability of pharmacological treatments will be assessed. Patients matching inclusion and exclusion criteria will be enrolled consecutively; each investigator will include the first 10 to 40 patients that will be visited as treatment resistant MDD.