Nervous System Hijack A nervous system hijack happens when stress, trauma, fear, rejection, or pressure takes over the body before the logical mind has time to respond. In that moment, you may not be “overreacting.” Your brain and body may be trying to protect you based on old experiences. The amygdala sounds the alarm. The body releases stress chemicals. The mind starts scanning for danger. The person may shut down, lash out, panic, people-please, isolate, or disconnect.