# Protocol for a randomized controlled trial to evaluate the efficacy of inhibitory control training for aggressive behaviours among individuals with co-occurring substance use disorder and gambling behaviour

## TL;DR

This study tests if training to improve inhibitory control can reduce aggression in people with substance use and gambling disorders in India.

## Contribution

First application of inhibitory control training for aggression in individuals with co-occurring substance use and gambling disorders in the Indian context.

## Key findings

- ICT may reduce aggression and improve inhibitory control in patients with substance use and gambling disorders.
- Changes in aggression and inhibitory control could correlate with reduced substance use and gambling behaviors.
- The study will assess outcomes at multiple time points to evaluate the intervention's long-term effects.

## Abstract

Aggression, substance use, and gambling behaviour often co-occur in a larger pattern of dysregulated behaviour. One of the factors that may underlie this phenomenon is impaired inhibitory control. Inhibitory Control Training (ICT) is an alternative intervention being tested for addressing addictive behaviours by targeting inhibitory control. Given the shared underlying mechanisms of these behaviours, applying ICT to aggression represents a possible extension of this intervention. This research will mark the first implementation of a cognitive bias modification approach to managing aggression among patients with co-occurring substance use disorder and gambling behaviour in the Indian context. A secondary aim of this study will be to assess whether changes in aggression and inhibitory control will be associated with reductions in substance use disorder and gambling behaviour.

A two-group, parallel randomized controlled trial will be carried out in 130 male in-patients at a tertiary care centre. Participants fulfilling the DSM-5 criteria for substance use disorders, and screening positive for problem (Score ≥ 1) or pathological (Score ≥ 5) gambling on the South Oaks Gambling Screen will be randomly allocated to either experimental (ICT) or control (Sham Training) group. The ICT consists of six 15-min sessions over three days, using a Go/No-Go paradigm with 100% contingency. ST is matched with the active training in terms of both stimulus exposure and response requirements, but reduces the contingency agreement to 50%, thereby preventing the formation of associations between aggressive stimuli and inhibitory responses. Primary and secondary outcome measures will be assessed at baseline, 1-day, 1-month, and 3-months post-intervention.

As aggression is frequently observed in individuals with addictive behaviors and is closely linked to deficits in regulatory behaviour, the intervention, if proven efficacious, could offer a cost-effective and time-efficient alternative to traditional cognitive-behavioral and anger management interventions. Conversely, should the intervention prove ineffective, the findings would indicate that this may not be a potential area for further exploration in this population.

The study protocol was registered prospectively with the Clinical Trials Registry of India (CTRI) on August 07, 2024 (Registration Number: CTRI/2024/08/072033) (URL: https://ctri.nic.in/Clinicaltrials/rmaindet.php?trialid=113292&EncHid=61291.44954&modid=1&compid=19).

The online version contains supplementary material available at 10.1186/s13063-026-09503-y.