The auditing function via Statistics > Auditing will tell you about accounts' history on the activity tab of any account - e.g. when the password was changed or when it failed to work because the password was entered incorrectly. It also says who made the change.the important actions that have happened accross your organisation.
For more detailed information about an individual account you can look at the activity tab on that account's detail page. You can jump to the account's details page from the audit page by clicking the account username.
This view will include things such as changes to the email address or password alongside things that appear at the organisation level.