Inhibitory control dysfunctions in anxiety: reactive vs. proactive mechanisms

Introduction

Inhibitory control is a core executive function that supports adaptive behavior in uncertain environments. It comprises two distinct components: reactive control, defined as the ability to inhibit an action in response to external stimuli, and proactive control, which involves the anticipatory engagement of reactive inhibitory mechanisms based on contextual information [1] [2]. Evidence suggests that inhibitory control may be altered in anxiety disorders, although the specific contribution of its reactive and proactive components to anxiety symptomatology remains unclear.

Aims

To investigate reactive and proactive inhibitory control in patients with anxiety disorders compared to healthy controls, and to explore their potential associations with broader self-regulatory processes relevant to anxiety.

Methods

Thirty-eight patients with anxiety disorders and thirty-eigth healthy controls, matched for age and sex, participated in the study. All participants completed a go-only task and a classical Stop Signal Task (SST). In the go-only task , participants performed reaching movements toward a peripheral target, providing measures of reaction time (RT) and movement time (MT), while being aware that they never had to inhibit their movements. In the SST, no-stop trials (67%), requiring target-directed movements, were randomly intermixed with stop trials (33%), in which participants were instructed to halt the movement upon presentation of a stop signal following the go signal. In stop trials, the stop-signal delay (SSD), i.e., the interval between go and stop signals, was dynamically adjusted via a staircase procedure to achieve approximately 50% successful inhibition. Participants were instructed to respond as quickly as possible without strategically slowing down. Primary outcome measures included stop-signal reaction time (SSRT), indexing reactive inhibition, and RT/MT modulation (the “context effect”), indexing proactive control [3]. Group differences in SSRT were assessed using independent-samples t-tests, while proactive inhibition was evaluated by comparing proportions using χ² tests. Effect sizes (Cohen’s d) and Bayes factors (BF₁₀) were reported alongside frequentist analyses.

Results

Patients with anxiety disorders showed significantly slower SSRT compared to healthy controls (222.6 ± 26.7 vs 204.4 ± 17.5 ms; t(72) = 3.49, p < .001, d = 0.81, BF₁₀ = 32), indicating impaired reactive inhibition . Regarding proactive inhibition, the between-group comparison did not reach statistical significance (χ²(1) = 0.29, p = .59); however, within-group analyses revealed a divergent pattern. Healthy controls showed a robust context effect (75.0%; χ²(1) = 9.00, p < .001), whereas anxiety patients exhibited only a marginal one (65.8%; χ²(1) = 3.79, p = .05), with a notably higher proportion of no-context responders (13.2% vs 5.6%). This pattern suggests a subtle, though not statistically robust, alteration in proactive inhibitory control in anxiety.

Conclusions

Patients with anxiety disorders show a clear impairment in reactive inhibitory control, reflected in slower stopping performance. Proactive inhibitory control, while not significantly different between groups, showed a subtly divergent pattern, suggesting a partial rather than full preservation. Together, these findings point to a gradient of inhibitory dysfunction in anxiety disorders, which represents a marker of underlying pathophysiology.

References

1. Mirabella, G., 2023. Beyond Reactive Inhibition: Unpacking the Multifaceted Nature of Motor Inhibition. Brain Sciences 13.
2. Van den Wildenberg, W.P.M., Ridderinkhof, K.R., Wylie, S.A., 2022. Towards Conceptual Clarification of Proactive Inhibitory Control: A Review. Brain Sci 12.
3. Mirabella, G., Pani, P., Ferraina, S., 2008. Context influences on the preparation and execution of reaching movements. Cogn. Neuropsychol. 25, 996-1010.