Be certain to find out how many family members have been afflicted and how long they have suffered. Also, ask about complications and related health problems people have suffered due to their illnesses. Has anyone in your family suffered from emotional or mental problems such as depression or obsessive-compulsive disorder. Find out the details of the illness including symptoms. This is an especially troublesome area to ask people about.
Many people are especially squemish when it come to questions of mental health.
Quirky relatives are not a favorite subject for discussion. But the knowledge is important both for you and future generations. Be sure to give your word to your source that under absolutely no circumstance will you use the information to hurt the informant or any other person and keep it . Find out all the details you can.