The consumption of drugs by adolescents may have a negative impact on cognitive performance as determined by functional neuroimaging tasks and neuropsychological assessments. It's clear that the younger generation abuses substances; the most prevalent ones are drugs, alcohol, and nicotine. Addiction to substances has detrimental consequences and can result in a range of behavioral, psychological, and cognitive problems. This experimental study aimed to investigate the effects of group activity-based intervention (GABI) on residents of drug and alcohol abuse rehabilitation centres' selective attentional cognitive function. Selective attention was measured using the Six Letter Cancellation Task Scale (SLCT). Thirty patients from a rehabilitation facility were included in the current investigation. Thereafter, two further groups were created: the 20-30 year old Active Group I and the Experimental Group I. For a duration of six weeks, participants in the experimental groups I attended three 45-minute sessions each week. The other group, which was the control/active group, continued with their usual rehabilitation routine. The Statistical Package for the Social Sciences, or SPSS, Version 26.0, was used for data analysis. The results suggest that there was no discernible improvement in Selective Attention with Group Activity-Based Intervention (GABI). No discernible changes were seen during the training, indicating that the experimental group I (aged 20 to 30) from this programme. Possible explanations for this include the brief duration of the intervention programme and the possibility that the participants' lifestyles impacted the study's findings. Furthermore, the study's findings may encourage more in-depth research with diverse populations and programme modifications in the future, enabling them to better assist participants' mental health in the context of drug and alcohol abuse.