One study reported different cognitive-control profiles in methamphetamine dependence and social media overuse. Its results do not establish that the two conditions are equivalent, or provide a clean causal ranking of their effects on the brain.
Zhang and colleagues conducted human behavioral experiments involving working-memory span and an adapted AX continuous-performance task. Each experiment compared a methamphetamine-dependent group with its own control group, and a social-media-overuse group with a separate control group. The second experiment recruited new participants.
The methamphetamine groups consisted of men in rehabilitation after physiological detoxification. Social media groups were recruited from college students using questionnaire and usage criteria. These were observational group comparisons, not randomized exposure to methamphetamine or social media.
In the working-memory experiment, both study groups scored below their respective controls. In the AX task, the methamphetamine group showed poorer performance on the reactive-control condition and a lower index of proactive versus reactive reliance after age adjustment. Its baseline and proactive-condition comparisons were nonsignificant.
The social-media group did not show significant differences from its controls on the corresponding baseline, reactive, proactive or reliance-index comparisons. A reactive-condition p value of 0.056 is a nonsignificant result, even though the paper describes a trend. A significant result in one comparison and a nonsignificant result in another do not themselves prove that the two effects differ.
Large age differences remained visible in the methamphetamine comparisons: for example, the second experiment’s group means were about 34 and 19 years. The authors adjusted for age, but adjustment is not equivalent to recruiting closely comparable groups. Education, recruitment setting, sex composition and severity also complicate comparisons across the two conditions.
No neuroimaging was performed in these experiments. Proposed explanations involving damaged brain circuits remain interpretations, rather than directly measured mechanisms. The findings support examining specific control components; they do not diagnose impairment in an individual, establish causation, or measure drug exposure.
Read our analysis of interpreting anticipation and task-specific brain findings.
Differential Impact of Methamphetamine Dependence and Social Media Overuse on Cognitive Control: Based on the Dual Mechanisms of Control Theory. doi:10.3390/bs15081086.