ADHD is still seen by many as a harmless childhood quirk. A little hyper. A little distracted. Maybe a bit forgetful. But behind the stereotypes lies a much darker truth, one that too often goes unspoken:
Untreated ADHD can be as dangerous to your health as smoking.
That may sound dramatic. But research confirms what many people with ADHD have felt all their lives that the cost of being unsupported isn't just missed deadlines or messy desks. It can be your health. Your future. Your life.
People don’t die from ADHD. But they die because of it.
One longitudinal study by Barkley & Fischer (2019) found that persistent ADHD was associated with a 12.7-year reduction in life expectancy. Similarly, a UK cohort study by O’Nions et al. (2025) showed a life expectancy deficit of 6.8 years for men and 8.6 years for women with ADHD. In public health terms, that’s on par with heavy smoking.
Why? ADHD brings a cascade of risks: poor sleep, substance use, difficulty managing chronic illness, car accidents, risky decisions. It’s a slow, accumulating toll.
In a landmark Danish study, Dalsgaard et al. (2015) reported that adults with ADHD are more than twice as likely to die from any cause, and nearly five times more likely to die from accidents. The risk was especially high in those diagnosed later in life and in women.
Self-harming behaviors and deaths from suicide are tragically higher in the ADHD community, especially among those who go undiagnosed or untreated. The emotional impulsivity, executive dysfunction, and coexisting depression can fuel moments of hopelessness.
Barbaresi et al. (2013) found that adults with childhood ADHD were 4.8 times more likely to die by suicide than their peers. A systematic review by Allely (2014) concluded that ADHD is a major risk factor for self-harm and suicidal behaviors, especially when paired with co-occurring emotional conditions.
Sun et al. (2019) showed that ADHD alone increases premature mortality, and the risk skyrockets with psychiatric comorbidities. Adults with ADHD and four or more co-occurring mental disorders had over 25 times the mortality risk compared to those without ADHD.
The pain isn’t just internal. ADHD can erode relationships, not because people with ADHD don’t care, but because life gets hard to manage, and guilt and overwhelm pile up.
Many adults with ADHD feel isolated. A UK study showed that the majority of adults who clearly meet the criteria for ADHD have never been formally diagnosed or treated. They’re just… surviving. Quietly. Alone. Undiagnosed in the workplace. Overwhelmed in parenting. Avoiding the doctor. Failing to understand themselves.