How Adult ADHD Symptoms Differ From Childhood PresentationsADHD doesn't simply disappear when someone turns 18. Core Attention Disorder Symptoms in AdultsDifficulty Focusing and Sustaining AttentionOne of the hallmark adult ADHD symptoms is the persistent struggle to concentrate on tasks requiring sustained mental effort. Forgetfulness Across Multiple ContextsMemory problems in adult ADHD often involve working memory deficits rather than permanent memory loss. Why Adult ADHD Symptoms Go Undiagnosed for YearsLimited Clinical Awareness and Training GapsOnly about 25% of adults with ADHD received their diagnosis before age 18. Adults with undiagnosed ADHD often unconsciously use substances to self-medicate for ADHD symptoms.