Ability to regulate emotions is a big one. If a person has a propensity to get fits of anger, or to become suddenly cold/unempathetic, or other emotions that seem disproportional to the situation… those point at trauma.

Another is addictions: drugs and alcohol of course, but also more subtle addictions like food, work, even working out. It’s tricky because you don’t want to pathologize every person, or dismiss uncomfortable truths because the messenger has a different lifestyle than yours. But yeah I try to at least consider these factors.