A handful of old alarms account for most sudden anger: threat to life or limb, insult, harm coming near your family, someone in your space, rivalry over a partner, and being trapped.

What the research says

A meta-analytic review across 75 studies found that heightened sensitivity to rejection was moderately associated with depression, anxiety, loneliness and borderline features. Being slighted is not a trivial matter for the nervous system, which is why insult sits alongside physical danger on any honest list. The pooled studies were largely measured at a single point in time, so they show the association rather than what leads to what.

Strength of evidence: one line of research. A single study, or a theoretical account.