In the US, approximately 1 in 6 US youth aged 6-17 had mental health problems, with an approximate 60% rise in suicidal ideation (SI) and suicide attempts (SA) since 2007, along with widening disparities by race/ethnicity, and gender. Little is known about the role of electronics as a causal effect in suicide attempts. We focus on the causal effect of the initiation of mobile phone use and the subsequent intensity of texting and social media use. We hypothesize that the causal effect varies by activity and that there will be differences in causal impacts by gender and race/ethnicity. We used the Adolescent Brain Cognitive Development® Study (ABCD) that followed 11,878 children (aged 9-10 at baseline) annually from 21 sites in 17 states, oversampling racial/ethnic minorities. ABCD was designed to be the largest long-term prospective cohort study of child development in the US. We focused on ages 9-12 in this study (data collected 2016-2021). We used instrumental variable bivariate probit models to measure the effects of initiating the use of mobile phones on suicide attempts and instrumental probit models to measure the effects of the intensity of texting and social media on suicide attempts. Our instruments were measures of school-based peer use of mobile phones, texting, and social media. Controls included child age, sex, race/ethnicity; parent education and marital status; family income; and time-fixed effects. We find that initiating mobile phone use results in a large increase in suicide attempts among females (average treatment effect: 0.208, 95% CI: 0.067, 0.350, p=0.01), but we could not detect an effect for males. With regard to intensity of use, we found increasing texting (per hour) was associated with a higher probability of suicide attempts among Hispanic females (marginal probability: 0.062, 95% CI: 0.001, 0.124, p=0.046) and Black females (marginal probability: 0.023, 95% CI: -0.002, 0.048, p=0.079). We found increasing social media use (per hour) was also associated with a higher probability of suicide attempts, but could only detect an effect for black females (marginal probability: 0.026, 95% CI: -0.001, 0.052, p=0.058). We could not detect an effect for males or other females. Caution is indicated with regard to the early initiation of mobile phone use among female children aged 9-12.