one study looked at reminiscence therapy for people with two types of dementia: alzheimer's disease and vascular dementia. those with alzheimer's disease experienced significant improvement of withdrawal (so they withdrew less and interacted with others more) compared with the control group immediately after intervention. participants suffering from vascular dementia showed significant improvement of withdrawal and cognitive function compared with the control immediately after intervention and after a 6-month follow up. sustained intervention may be required to maintain these effects over time, especially in elderly people with alzheimer's disease whose improvement in withdrawal was no longer seen after 6 months.