The very large and sudden changes in mental health and behavior between Millennials and Gen Z are likely not a coincidence: They arose from the fastest adoption of any technology in human history. The case for technology, especially social media, causing the rise in mental health issues among young people relies on four primary pieces of evidence: 1) timing, 2) impact on day-to-day life, 3) group-level effects, and 4) the impact on girls. Only a small amount of this evidence was available when I was writing iGen in the mid-2010s—the rest has emerged since then.
