Anger in Parkinson's disease: A case-control study

Cognitive-psychiatric features of Parkinson's disease (PD) are common and they may be as disabling as the motor features of the disease. PD has been associated with stoic and inflexible personality traits. While many features of personality have been studied in PD, a systematic study of anger trait and anger expression in PD has not been performed. We used the Spanish adapted version of the state-trait anger Expression Inventory-2 (STAXI-2), comprised of six scales and an anger expression index, to measure anger trait and anger expression. There were 126 PD patients with depressive symptoms and 126 age- and gender-matched controls. PD patients had lower levels of state anger (15.8 ± 3.1 vs. 17.9 ± 5.3, P < 0.001), trait anger (19.2 ± 5.3 vs. 20.7 ± 6.0, P < 0.05), anger expression-out (9.0 ± 2.5 vs. 10.5 ± 3.0, P < 0.001), and anger expression index (26.1 ± 8.8 vs. 29.6 ± 9.4, P = 0.002); and higher levels in anger expression-in (14.0 ± 3.4 vs. 12.2 ± 3.2, P < 0.001), anger control-out (18.6 ± 5.0 vs. 16.1 ± 5.0, P < 0.001), and anger control-in (14.3 ± 4.7 vs. 13.0 ± 4.5, P < 0.05) than controls. These differences persisted in analyses adjusting for age, gender, and depressive symptoms. Conclusions: PD patients showed lower levels of external expression of anger and higher levels of control of anger. Our results demonstrate another dimension to the stoic personality trait seen in PD.