'apsychia' originates from Greek, specifically from the elements 'a-' + 'psychē', where 'a-' meant 'without' and 'psychē' meant 'soul' or 'mind'.

'apsychia' was formed from classical Greek elements and passed into medical/technical usage in modern Latin and English (19th century onward) as a term for lack of mental activity.

Initially it meant 'without soul/mind' in a literal sense, but over time it evolved into a clinical term for 'loss or absence of mental activity or consciousness'.