 Assessments Demographic data will be collected at the start. Psychological tests for depression and anxiety and neuropsychological tests of cognitive functioning will be done at the start, at 3-months and at 9-months, the end of the study. A urine sample will be collected at the start and at the end of the study; blood, fecal and saliva samples will be collected at all three time points. Participants will also undergo a brain neuro-imaging scan at the start of the study and at the 3-months interval. 