You can find out if someone is narcissist by observing the behaviour, attitudes and reactions. There are no blood tests, MRI or scan that can identify someone as narcissist. Some of the behaviour to watch out for includes:
Exaggerated need for attention and validation – narcissists always yearn for so much attention and constant validation
Need for control – they do as much as they can to always be in control and their sense of entitlement makes it seem logical to them that they should be in control.
Lack of empathy – they have very little ability to empathize with others. They tend to be selfish and self-involved and are usually unable to understand what other people are feeling.
Other things to watch out for are: need for perfectionism, lack of responsibility and lack of boundaries.