<qa>  What will be done at the start of the study?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. 