Objectives: : To investigate whether alexithymia is linked to the disease process or to psychopathology, particularly depression, in Parkinson disease (PD) patients.
Design: : Cross-sectional study.
Setting: : Neuropsychiatry outpatient clinic.
Participants: : One hundred PD patients and 100 comparison subjects (CS).
Measurements: : PD patients and CS underwent a clinical and neuropsychiatric evaluation. Alexithymia was assessed with the 20-item Toronto Alexithymia Scale (TAS-20). Severity of depressive symptoms was measured with the Beck Depression Inventory. A structured psychiatric interview was used to diagnose major and minor depression. Logistic regression analyses with 95% confidence intervals (CI) were used to assess the association between alexithymia and PD.
Results: : Alexithymia occurred twice as often in PD patients (22%) as in CS (11%) and major depressive disorder occurred twice as often in CS (30%) than in PD (16%). The frequency of minor depression was almost identical (about 40%) in the 2 groups. Alexithymia was also associated with PD independently from depression. Indeed, after adjustment for sociodemographic factors, antidepressant use and depression severity, PD patients had an almost fourfold higher risk of having alexithymia (OR: 3.9, 95% CI: 1.5-10.0) and 24 times increased odds of having high scores on the TAS-20 items assessing difficulty in identifying emotions than CS (OR: 23.7, 95% CI: 10.1-55.6).
Conclusions: : Our findings suggest that alexithymia is a depression-independent phenomenon in PD patients and may be associated with the disease process. Alexithymia is an important nonmotor symptom of PD and should be considered in patient assessment and management.