ADHD and ADD: Symptoms, Differences, Diagnosis and Treatment

What ADHD is

You sit down to study and remember three other things you need to do. You open your laptop and, twenty minutes later, find yourself reading something unrelated. You have dozens of ideas but struggle to finish them — then comes the familiar thought, "why can't I just focus like everyone else?"

Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterised by a persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning. The National Institute of Mental Health describes ADHD as persistent inattention, hyperactivity and/or impulsivity that interferes with functioning across school, work, relationships and home life.[2] It affects children, adolescents and adults, and the visibly hyperactive child is only one of several possible presentations.

ADHD vs ADD

This is one of the most common questions people ask. The short answer: ADD is older, outdated terminology; ADHD is the current diagnostic term. Historically "ADD" described attention difficulties without prominent hyperactivity. Current diagnostic systems no longer treat ADD as a separate disorder — instead, ADHD can present predominantly through inattentive symptoms. So someone who says "I think I have ADD, not ADHD, because I'm not hyperactive" may be describing the predominantly inattentive presentation of ADHD. WHO's ICD-11 specifically identifies ADHD with predominantly inattentive, predominantly hyperactive-impulsive and combined presentations.[1]

The three presentations

Predominantly inattentive is often the least recognised. There may be little visible hyperactivity; instead, difficulty sustaining attention, organising tasks, following through, remembering appointments, keeping track of belongings, and resisting distraction. The CDC lists losing things, being easily distracted, forgetting daily activities and trouble organising tasks among ADHD symptoms.[4]

Predominantly hyperactive-impulsive does not necessarily mean running around. In adults it can be internal restlessness — fidgeting, difficulty staying seated, talking excessively, interrupting, answering before a question is finished, and difficulty waiting.

Combined means both inattentive and hyperactive-impulsive symptoms are clinically significant. This is not "more ADHD" — it simply describes the pattern most prominent at the time of assessment. ICD-11 distinguishes these presentations by the predominant pattern of clinically significant symptoms.[1]

ADHD in adults

ADHD does not disappear at 18; the presentation changes. A child who lost homework may become an adult who misses deadlines; a child who couldn't sit through lessons may find long meetings difficult. Common adult difficulties span attention (losing focus, careless mistakes), organisation (clutter, missed appointments, difficulty prioritising), time management (chronic lateness, procrastination, last-minute intensity), impulsivity (interrupting, impulsive purchases) and restlessness. NIMH identifies difficulties with organisation, procrastination, time management, completing projects, restlessness and impulsivity among adult ADHD-related difficulties, and notes childhood hyperactivity may become less obvious while restlessness and attention problems continue.[3]

A common misunderstanding: "But I can focus for hours on things I like." Attention is not a simple on/off switch — motivation, novelty, urgency and interest all influence engagement, so intense focus on an engaging activity does not rule out ADHD. Equally, it is not by itself evidence of ADHD; a broader assessment is needed.

Women, girls and late recognition

ADHD can be missed in girls and women, particularly when inattentive symptoms dominate. A child who is not disruptive may not attract attention; difficulties can appear as daydreaming, forgetfulness, disorganisation and chronic procrastination. NIMH notes boys and men tend to show more hyperactive-impulsive symptoms, while girls and women are more likely to have an inattentive presentation.[2] Many adults reach their thirties or forties without a diagnosis because they compensated — until university, a demanding job, or parenthood removed the external structure.[3]

How ADHD is assessed

There is no blood test, brain scan or online quiz that can diagnose ADHD. Diagnosis is a comprehensive clinical assessment exploring current symptoms, childhood behaviour, school and work history, relationships, sleep, anxiety, depression, medical and developmental history, and symptoms across different environments. For adults, childhood history matters because ADHD is neurodevelopmental; NIMH notes adult assessment may draw on childhood records, school reports and information from people who knew the person as a child.[3] The CDC similarly notes diagnosis involves multiple steps and that other conditions can produce ADHD-like symptoms.[5]

What can look like ADHD

"I can't concentrate" can reflect ADHD — or anxiety, depression, sleep deprivation, stress, or several factors at once. Severe anxiety can impair concentration; depression can affect motivation, memory and task initiation; poor sleep impairs attention and executive function. The distinction often depends on the pattern and developmental timeline: attention problems appearing only after a period of anxiety or a depressive episode give different information from a lifelong pattern beginning in childhood. This is one reason self-diagnosis from a checklist can mislead.[5]

How ADHD is treated

Treatment is individualised and may combine medication, psychotherapy, behavioural interventions, psychoeducation, executive-function strategies, parent training for children, and workplace or school support. NIMH identifies medication and psychosocial interventions among established approaches.[2] Stimulant medications are commonly used, with non-stimulant options available; medication should be prescribed and monitored by a qualified medical professional and never started on the basis of an online screening result.[3] Psychological support can help with procrastination, planning, emotional regulation, negative self-beliefs and any co-occurring anxiety or depression.

ADHD is not a lack of intelligence or effort. Many people with ADHD have tried extremely hard for years; the difficulty is consistently directing and regulating attention, impulses and executive functions the way a situation demands. Understanding the pattern can replace self-blame with a more useful question: "What support and strategies would make this easier?"

Should I take an ADHD test?

If you have persistent difficulties with attention, organisation, impulsivity or hyperactivity, a validated screening tool is a reasonable starting point — but treat the result as a signal, not a diagnosis. A high score means "it may be useful to speak with a qualified professional," not "I definitely have ADHD."[5] Rooh Mind Care offers a free, anonymous ICD-11 screening that includes an ADHD module based on the WHO Adult ADHD Self-Report Scale; it produces a summary you can bring to a proper assessment.

Related reading: psychological & ADHD assessment, social anxiety disorder, depression, and psychiatric consultation.