Question: when was the term shell shock first used
[{'answer': '1915', 'provenance': [{'wikipedia_id': '22290028', 'title': 'Shell shock', 'start_paragraph_id': 7, 'start_character': 170, 'end_paragraph_id': 7, 'end_character': 174, 'bleu_score': 1.0, 'section': 'Section::::Origin.\n'}]}, {'provenance': [{'wikipedia_id': '22290028', 'title': 'Shell shock', 'start_paragraph_id': 7, 'start_character': 0, 'end_paragraph_id': 7, 'end_character': 390, 'bleu_score': 0.9155272930874561, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17806897327810209537}, 'section': 'Section::::Origin.\n'}]}]