Irritability

Irritability is an excessive response to stimuli.

The term irritability is both used for the physiological reaction to stimuli and for the psychological, abnormal or excessive sensitivity to stimuli.

Irritability may manifest in behavioural responses to both physiological as well as behavioural stimuli - the latter including areas of environmental, situational, sociological, and emotional stimulus.

Causes
Irritability can result from conditions such as:
 * combat stress reaction
 * depression
 * dysmenorrhea
 * heat
 * headache
 * hunger
 * hyperthermia
 * hypothyroidism
 * lead poisoning
 * mastoiditis
 * sleep apnea
 * stress
 * tiredness