Avicenna, The Canon of Medicine, said,
“An angry person gives out a definite atmosphere a feeling of being "on edge." The effect on bystanders depends on their dominant emotional state; in some it provokes quarrelsomeness in others perplexity owing to the discovery that the person is unapproachable. Silence and appropriate interior exercises are indicated.”
“Angry words produce mental "sores"; they may heal, or they may be kept going or they may be re-opened, or become incurable. An outburst of anger may be provoked by a clash of interests. These vary widely.”
“Thus, two wills may clash; the function of one organ may clash with that of another (e.g. menstrual irritability or outburst of temper); clash of duty with self-will. The intensity of the outburst is according to the principle of jelal-jemal.”