Severe deterioration in cognitive function and personality in five patients with long-standing diabetes: a complication of diabetes or a consequence of treatment?

Changes in mood, personality, and social function were examined in a group of five Type 1 diabetic patients, aged 50 to 66 years, with duration of diabetes from 24 to 47 years. Information on medical history was obtained from their carers and hospital records. All patients had experienced multiple episodes of severe hypoglycaemia and had impaired awareness of hypoglycaemia. Cerebral dysfunction predated the development of minimal diabetic complications and had been apparent for between 1 and 17 years. The carers assessed the pre-morbid and present behaviour and personality of the patients using standard questionnaires. Significant deteriorations were demonstrated in cognitive (p = 0.04) and social functions (p = 0.04), compared with assessment of pre-morbid function. Patients had tended to become more neurotic (p = 0.08) and less extravert (p = 0.07). All of the patients and three of the carers recorded scores suggestive of psychiatric morbidity on the General Health Questionnaire. The patients had experienced loss of employment and the carers described a reduction in the patients' social interactions. Although the aetiology of their cerebral dysfunction can not be definitely ascertained this case series emphasizes the need for long-term prospective studies in patients with diabetes of long duration to assess the impact of the disorder on cognitive and social abilities particularly where there is evidence of cerebral dysfunction. The need for professional support for the carers of such patients should be recognized.