ADD vs ADHD: What's the Difference?

If you or someone you know was diagnosed with ADD years ago, or if you have been using the term to describe symptoms in yourself or a child, here is the first thing to know: ADD is not a current medical diagnosis.

It has not been since 1987.

What you are describing is ADHD. More specifically, it is likely the predominantly inattentive presentation of ADHD, the form that tends to look quiet, internal, and like a character flaw rather than a neurodevelopmental condition. Understanding what changed in the diagnostic terminology and what those changes mean clinically can make a real difference in whether someone gets an accurate assessment and appropriate treatment.

What This Page Covers

• Why ADD no longer exists as a clinical diagnosis
• What the DSM-5 says about ADHD presentations
• The key differences between inattentive, hyperactive, and combined types
• What changed between DSM-IV and DSM-5
• Why inattentive ADHD is the most underdiagnosed presentation
• How SiggyMD supports adults with co-occurring ADHD and mood or anxiety symptoms

The Short Version of the ADD vs. ADHD History

ADD (attention deficit disorder) first appeared in DSM-III in 1980. It described children with significant attention and impulse control difficulties, and it came in two versions: with or without hyperactivity.

The DSM-III-R revision in 1987 dropped the ADD label entirely and replaced it with ADHD. The reasoning was that inattention and hyperactivity are not separate conditions. They are different expressions of the same underlying neurodevelopmental pattern. ADD isn’t an accepted medical term or diagnosis anymore.

The DSM-IV (1994) recognized three subtypes: predominantly inattentive type (the closest ancestor to the old ADD), predominantly hyperactive-impulsive type, and combined type.

The DSM-5 (2013) kept the three categories but made a meaningful linguistic and clinical change: it replaced “subtypes” with “presentations.” The language change matters. A subtype implies a fixed category you belong to permanently. A presentation acknowledges that your symptom profile can change over time. Someone who presents as predominantly inattentive at 35 may have had more hyperactive-impulsive features at 10.

The Three Presentations in Plain Language

Predominantly Inattentive Presentation

This is what most people informally still call ADD. ADHD Predominantly Inattentive Presentation is characterized by sustained attention failures, disorganization, forgetfulness, and distractibility.

In adults, this looks like: starting projects and not finishing them, perpetual lateness, difficulty sustaining focus on tasks that are not intrinsically engaging, frequently losing things needed for tasks, missing obligations that are clearly on the calendar, and a sense of chronic scatteredness that feels like a personality trait rather than a neurological condition.

What makes this presentation hard to identify is that inattentive ADHD may be the most difficult to diagnose as it is often dismissed as the person being ‘spacey’ or ‘apathetic,’ or experiences are attributed to anxiety or a mood disorder. The quiet presentation does not disrupt others, so it rarely prompts a referral, especially in childhood.

Predominantly Hyperactive-Impulsive Presentation

This is the culturally familiar image of ADHD: fidgeting, interrupting, difficulty waiting, excessive movement. In children, this means literally climbing and running. In adults, hyperactivity is often internal: a constant mental noise, restlessness, difficulty tolerating quiet.

This presentation tends to be diagnosed earlier because it affects other people. A hyperactive, impulsive child disrupts classrooms and family routines in visible ways that prompt evaluation. The inattentive child who stares out the window often does not.

Combined Presentation

The combined type meets threshold criteria for both inattentive and hyperactive-impulsive presentations. In adults, the combined type is the most common presentation. Hyperactive symptoms typically become more subtle with age, shifting from physical restlessness to internal noise. Inattentive symptoms often remain stable or become more visible as life demands increase.

What the DSM-5 Changed and Why It Matters

The 2013 DSM-5 revision made four changes that significantly affected who gets diagnosed with ADHD, particularly adults.

Age of onset. DSM-IV required that symptoms be present before age 7. DSM-5 raised this to age 12. That single change opened the door for a large group of adults who had struggled their whole lives but couldn’t recall clear symptoms in early childhood, or who had compensated well enough in structured school environments that their difficulties weren’t noticed until demands increased.

Adult symptom threshold. DSM-5 lowered the required number of symptoms for adults to five (in either inattentive or hyperactive-impulsive clusters) from six. This reflects the clinical reality that hyperactive symptoms often become less visible with age while the condition continues to impair functioning.

Presentations not subtypes. The shift from “subtype” to “presentation” was not cosmetic. It formalized what clinicians already knew: symptom profiles are not fixed. Someone’s dominant presentation can shift over the lifespan, particularly as hyperactivity decreases.

ADHD and autism can co-occur. DSM-IV explicitly excluded an ADHD diagnosis if the person had autism spectrum disorder. DSM-5 removed this exclusion, reflecting research showing the two conditions co-occur at significant rates and both warrant clinical attention.

The Inattentive Presentation Is Chronically Underdiagnosed

The predominantly inattentive presentation, what people still call ADD, is the most common ADHD subtype and also the most frequently missed. Several patterns drive this gap.

First, the symptoms are internal. No one is disrupted. No teacher sends a note home. The child who drifts, loses things, and cannot seem to finish anything is unlikely to be referred for evaluation unless someone explicitly looks for it.

Second, women are significantly more likely to have the inattentive presentation, and they are significantly less likely to receive an ADHD diagnosis. Women are more likely to have inattentive symptoms than hyperactive symptoms, which may be less likely to lead to a referral and diagnosis. The gender gap in ADHD diagnosis is partly a symptom-presentation gap.

Third, inattentive ADHD is easily mistaken for anxiety or depression. Both involve difficulty concentrating, low energy, and underperformance. More than 70% of adults with ADHD have at least one comorbid psychiatric disorder. Approximately 55% have depressive disorders, 47% have anxiety disorders. When a mood or anxiety diagnosis comes first, ADHD often remains unrecognized underneath.

What an Accurate Evaluation Looks Like

For adults, an ADHD evaluation is not a questionnaire. It is a clinical interview covering current symptoms, functional impairment across multiple settings, and evidence that symptoms were present before age 12. Standardized rating scales (most commonly the Adult ADHD Self-Report Scale, ASRS-v1.1) are typically part of the process.

The clinician must also rule out other conditions that produce overlapping symptoms: anxiety, depression, sleep disorders, thyroid dysfunction, and substance use. These conditions can exist alongside ADHD, but they are not substitutes for an ADHD diagnosis.

For clinical paperwork, insurance, and accommodations, the correct designation is ADHD with a presentation specifier (predominantly inattentive, predominantly hyperactive-impulsive, or combined). ADD is no longer in the DSM-5, but ADHD covers the same ground.

About SiggyMD

ADHD very frequently co-occurs with anxiety and depression. SiggyMD’s clinical scope covers those co-occurring conditions directly.

If you have been treated for anxiety or depression without fully resolving your symptoms, and you recognize the pattern of inattentive ADHD in the descriptions above, the anonymous intake at SiggyMD captures the full clinical picture. A licensed prescriber can evaluate for the overlapping presentations and identify whether the treatment plan reflects all the relevant conditions.

“A significant number of adults come in for anxiety or depression and have unrecognized inattentive ADHD underneath,” says Daniel Montville, MD, Psychiatrist at SiggyMD. “The anxiety and depression are real and require treatment. But treating those without identifying the ADHD often leaves people wondering why they feel better emotionally but still can’t function the way they want to.”

The anonymous intake requires no name, email, or account to begin. A licensed prescriber reviews every clinical decision.

For more on ADHD in adults and its presentation across the lifespan, read what ADHD actually is or explore the full picture of ADHD symptoms in adults.

Start your anonymous intake with SiggyMD to discuss attention, mood, and anxiety symptoms with a licensed prescriber who can evaluate the full picture.

What Members Are Saying

SE

S.E., 33

Late-Diagnosed ADHD, Predominantly Inattentive

“I always thought I had attention problems because I was anxious. My therapist treated the anxiety for two years and I got better emotionally but still couldn’t follow through on anything. When someone finally looked at the ADHD piece, the whole picture made sense. They’re not the same thing, and treating one doesn’t fix the other.”

PK

P.K., 27

ADHD, Combined Type

“My whole life I was told I had ADD. I had no idea that wasn’t even a real diagnosis anymore. When I finally had a proper evaluation as an adult, I was told I had ADHD combined type. Learning that my symptoms could shift, and that the hyperactivity I still feel is just more internal now, actually helped me understand what I was dealing with better.”

Member stories reflect real experiences. Names and identifying details have been changed to protect privacy. Results vary. You can begin anonymous intake without an account, name, email, or payment.

Sources

1. Cleveland Clinic. ADD vs. ADHD: What’s the Difference? Accessed June 2026.

2. National Institute of Mental Health. Attention-Deficit/Hyperactivity Disorder. NIMH. 2024.

3. American Psychiatric Association. ADHD in Adults. APA. Updated 2025.

4. SAMHSA. DSM-5 Changes: Implications for Child Serious Emotional Disturbance. 2016.

5. Shore C, et al. ADHD Diagnosis and Treatment in the United States. National Academies Press. 2024.

6. ScienceInsights. Is ADD in the DSM-5 or Replaced by ADHD? Accessed June 2026.

7. Neurolaunch. DSM-5 ADD vs ADHD: Key Differences and Diagnostic Changes. Accessed June 2026.

8. ADDitude Magazine. ADD vs. ADHD: Symptoms, Treatment, Definitions. Accessed June 2026.

9. Centers for Disease Control. Data and Statistics About ADHD. CDC. Accessed June 2026.