An in vitro method for performing a differential diagnosis of neurodegenerative diseases in a subject, said subject being selected among subjects suffering from Alzheimer's disease, mental depression, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's disease, progressive supranuclear palsy, and/or Parkinson's disease with dementia, said method comprising the steps of: a) determining at least five criteria of said subject, said at least five criteria comprising: the age of said subject, a score of said subject to a questionnaire adapted for screening cognitive function, a dopamine concentration in one blood sample of said subject, an adrenaline concentration in one blood sample of said subject, a noradrenaline concentration in one blood sample of said subject; b) determining for each neurodegenerative disease a value V disease criterion per criterion by comparing a measured value VAL criterion corresponding to the obtained criterion in step a) with a range of reference values as follows: i. V disease criterion = 0 if VAL criterion is outside the range of reference values MINI disease criterion − MAXI disease criterion, or ii. V disease criterion = 1 + K VAL criterion − MINI disease criterion MAXI disease criterion − MINI disease criterion if VAL criterion is within the range of reference values wherein MINI disease criterion and MAXI disease criterion represent respectively the minimum and the maximum values of the range of reference values with respect to each neurodegenerative disease in function of each criterion, wherein K is a mathematical parameter comprised between 0 and 0.1 c) calculating a global note for each neurodegenerative disease by summing the values V disease criterion each multiplied with a weighting factor; d) determining, based on the highest global note calculated in step c) for all of neurodegenerative diseases, whether said subject suffers from Alzheimer's disease, mental depression, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's disease, progressive supranuclear palsy, Parkinson's disease with dementia or mixed dementia. a) determining at least five criteria of said subject, said at least five criteria comprising: the age of said subject, a score of said subject to a questionnaire adapted for screening cognitive function, a dopamine concentration in one blood sample of said subject, an adrenaline concentration in one blood sample of said subject, a noradrenaline concentration in one blood sample of said subject; b) determining for each neurodegenerative disease a value V disease criterion per criterion by comparing a measured value VAL criterion corresponding to the obtained criterion in step a) with a range of reference values as follows: i. V disease criterion = 0 if VAL criterion is outside the range of reference values MINI disease criterion − MAXI disease criterion, or ii. V disease criterion = 1 + K VAL criterion − MINI disease criterion MAXI disease criterion − MINI disease criterion if VAL criterion is within the range of reference values wherein MINI disease criterion and MAXI disease criterion represent respectively the minimum and the maximum values of the range of reference values with respect to each neurodegenerative disease in function of each criterion, wherein K is a mathematical parameter comprised between 0 and 0.1 i. V disease criterion = 0 if VAL criterion is outside the range of reference values MINI disease criterion − MAXI disease criterion, or ii. V disease criterion = 1 + K VAL criterion − MINI disease criterion MAXI disease criterion − MINI disease criterion if VAL criterion is within the range of reference values wherein MINI disease criterion and MAXI disease criterion represent respectively the minimum and the maximum values of the range of reference values with respect to each neurodegenerative disease in function of each criterion, wherein K is a mathematical parameter comprised between 0 and 0.1 wherein MINI disease criterion and MAXI disease criterion represent respectively the minimum and the maximum values of the range of reference values with respect to each neurodegenerative disease in function of each criterion, wherein K is a mathematical parameter comprised between 0 and 0.1 c) calculating a global note for each neurodegenerative disease by summing the values V disease criterion each multiplied with a weighting factor; d) determining, based on the highest global note calculated in step c) for all of neurodegenerative diseases, whether said subject suffers from Alzheimer's disease, mental depression, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson's disease, progressive supranuclear palsy, Parkinson's disease with dementia or mixed dementia.