Aim: Adult patients with type 2 diabetes were classified using the Temperament and Character Inventory (TCI). This classification was used to propose effective therapeutic approaches based on subtypes of psychological characteristics.
Methods: The TCI and various psychological tests were administered to 89 patients (54 men and 35 women). Cluster analysis was performed using three temperament factors of the TCI as variables for subclassification: novelty seeking (NS), harm avoidance (HA) and reward dependence (RD).
Results: The patients were divided into two clusters based on the TCI results. Cluster 1 had a low NS/high HA/low RD pattern, which indicated resistance to change and lack of cooperativeness, and results of other tests indicated that patients in cluster 1 were obsessional and had weak intention and personality disorder symptoms. In contrast, cluster 2 had a high NS/low HA/high RD pattern, indicating a socially active person who easily becomes dependent on others, and results of other tests indicated that these patients were histrionic and less anxious. In cluster 1 there was a significant negative correlation between hemoglobin A1c (HbA1c) and SD-1 (TCI self-directedness) ‘responsibility’ and a significant positive correlation between HbA1c and State anxiety of State–Trait Anxiety Inventory. In cluster 2 there was a significant positive correlation between HbA1c and HA-2 ‘fear of uncertainty’.
Conclusions: Patients with type 2 diabetes were classified using the TCI into two subgroups. These two groups differed in psychological characteristics and had a different pattern in correlation with glycemic control.