Abstract
Impulsivity is a multidimensional, cross-diagnostic behavioural construct that has been described in various psychiatric disorders including obsessive-compulsive disorder (OCD) and Tourette syndrome (TS). Different interpretations of results in the past have raised the question of heightened impulsivity as an explanatory model for self-described impulsive behaviour, especially in OCD. Our study included 16 patients with OCD, 14 patients with TS, and 28 healthy control subjects (HC). Self-assessed impulsivity was examined by the Barratt Impulsiveness Scale-11 (BIS-11), and the behavioural test used was the immediate and delayed memory task (IMT/DMT). Significantly heightened self-assessed impulsivity of the patient collective compared to HC could be observed in in only one dimension: lack of attention (χ(2) (2) = 24.910, p < 0.001). Post-hoc tests were performed using Bonferroni adjusted alpha levels of 0.0167 per test (0.05/3) and revealed significantly higher scores in patients with OCD (M = 19.57, SD = 2.82), z = 4.292, p < 0.001 as with TS (M = 19.38, SD = 3.62), z = 3.832, p < 0.001 compared to HC (M = 13.78, SD = 3.18). In patients with OCD, correlations between the dimension of obsessive thoughts with a lack of attention in the form of first-order factor cognitive instability could be shown (n = 14, p = 0.024, r(s) = 0.599) while in patients with TS, tic symptomatology correlated significantly with second-order factor attentional impulsivity (n = 12, p = 0.027, r(s) = 0.635). In behavioural testing, no significant group differences could be observed either in impulsive behaviour (IMT: χ(2) (2) = 4.709, p = 0.824; DMT: χ(2) (2) = 0.126, p = 0.939) or in sustained attention (IMT: χ(2) (2) = 0.388, p = 0.095; DMT: χ(2) (2) = 0.663, p = 0.718). Heightened impulsivity as an explanatory model for the observed lack of attention, especially in patients with OCD, should be questioned and interpretation biases considered in the future. The necessity of a multidimensional approach to the research of impulsivity is underscored by our results.