I heard that a teenager was admitted to hospital due to shrinking amygdala. As far as my limited psychiatric knowledge is concerned, shrinking amygdala means the patient is likely to find it hard to control emotion. Irregular and intense emotion is a telling sign of Borderline Personality Disorder (BPD).
Many BPD patients experienced neglect or abuse by parents or main carers during childhood and the growth of their amygdala was limited due to extreme shock. As they reach adulthood, their amygdala is eight per cent smaller than normal adults. It is the gap of eight per cent that creates the difficulty for them to emotionally control themselves.
On Quora.com, some writers wrote that they witnessed persons with BPD swinging between the moods of happy, angry, sad and joy within five minutes. Another account is that some BPD patients could experience extreme mood swings for five to six times a day, or 11 to 12 times on very emotionally unstable days. Some BPD patients admitted on the forum that they feel angry about themselves every passing minute and second.
A miss is as good as a mile; the size of amygdala has perhaps explained the saying.