The COVID-19 pandemic has created a psychoactive substance use crisis in many countries, including México. Remote valid tools to identify high-risk groups in need for treatment are a prerequisite for cost-effective interventions in primary care settings. To determine the validity and correlates of the remote applications of the Alcohol, Smoking, and Substance Involvement Screening Test (ASSIST) with sex, age, and psychological care-seeking, offered remotely in primary settings, during the COVID-19 pandemic in Mexico, a total sample of 19,109 Mexicans, with an average age of 34.38 years ( SD = 12.28, range = 18–80), 65.8% of whom were women ( n = 12,578), 29.6% in lockdown (5,660), 39.8% in partial lockdown (7,611), 30.60% not in lockdown (5,838), and 14.75% of whom were seeking psychological care ( n = 2,819), completed ASSIST through a programmed Web application. The dimensionality of the scale to verify construct validity evidence was achieved through a confirmatory factor analysis model (CFA). We represented the distribution of subjects by sex, age, lockdown condition, and psychological care-seeking, based on their lifetime consumption in 2021. We also compared the total distribution by consumption risk level and recommended type of intervention, psychological care-seeking, and age. The tool included ten dimensions (one for each substance, such as tobacco use), confirmed through the CFA. In general, our findings indicated that men reported high lifetime psychoactive substance use and risky drug use levels. A high percentage of 18 to 19-year-old women reported lifetime tobacco and alcohol use. Additionally, a high number of all-age women reported lifetime sedative and opioid use. Also, a high proportion of partially lockdown participants reported lifetime drug use. Moreover, a high percentage of subjects seeking psychological care were at a moderate and high risk of drug use, which required brief or intensive treatment. Our findings indicate that it was possible to validate the factor structure of the programmed ASSIST for remote use. More men than women reported high lifetime psychoactive substance use and risky levels because of their consumption. At the same time, younger women reported similar and even higher lifetime tobacco, alcohol, and cocaine use than same-age men. More all-age women reported lifetime use of sedatives than all-age men. More all-age partially lockdown participants reported lifetime use of drugs. In general, subjects at greater risk and those requiring psychological care are more likely to seek care. Community and primary care screening will make it possible to implement effective early interventions to reduce the substance use risks associated with health emergencies. Future studies are required to determine the diagnosis of substance use disorders to evaluate the cut-off points in the screening test to discriminate between the presence and absence of symptoms and evaluate the effect of rem...