In the present study we tested two polymorphisms in the alpha-2 macroglobulin gene, a 5 bp deletion at the 5' splice site of exon 18 and a G/A point mutation (V1000I) in exon 24, in a sample of 118 healthy, non demented controls and 238 consecutively recruited gerontopsychiatric patients, diagnosed as: Alzheimer's disease (N=88), mild cognitive impairment (N=32), subjective cognitive complaints (N=54) and depression/other psychiatric disorders (N=64).