How Adult ADHD Is Diagnosed: The Process Step by Step

Between "I think I have it too" and "I was diagnosed" there is a process, and it is longer than most people expect.

In the time between saying that sentence and the appointment, I was afraid of two things above all. The first was being told "you are exaggerating." The second was that what I had to say would not be enough; because what I remembered was scattered and I had no documents at all.

Now I know that knowing in advance how the process works takes away most of that fear. This article is for that.

Which clinic to apply to, why neurology does not do this job and where the psychologist stands in the process, I explained step by step in the article which doctor to see.

Who makes the diagnosis

In Turkey, ADHD is diagnosed by psychiatrists. Psychologists can carry out assessments and administer tests and can provide therapy; the diagnosis and the medication decision belong to the physician. I wrote in detail about where to apply in the article where to get an ADHD diagnosis as an adult.

What the process consists of

A structured interview. An assessment carried out in a set order with fixed questions. One of the tools often used with adults is DIVA; it asks about each diagnostic criterion separately for both childhood and adulthood. The European consensus statement describes this kind of structured interview as the backbone of assessment (Kooij et al., 2019).

Rating scales. ASRS is the World Health Organization's short screening scale (Kessler et al., 2005). The Conners and Wender Utah scales are also used. All of them count as supporting data; none of them makes the diagnosis on its own.

Childhood history. DSM-5 looks for symptoms to have started before age twelve (APA, 2022). That is why report card comments, family accounts and old memories are asked for. For many people diagnosed late this part is hard, because remembering is not reliable either.

The two-setting rule. The symptoms need to appear in at least two different settings: home and work, school and social life. The aim is to show that the problem does not stem from the conditions of a single setting.

Functioning. A symptom alone is not enough. Real harm is looked for at school, at work or in relationships. This is the sine qua non of the diagnosis.

Neuropsychological tests. Tests measuring attention and executive functions fill in the picture but are not decisive. A normal test result does not rule out ADHD.

The most misunderstood condition

Among these three conditions, the one least talked about and most decisive is functioning.

For a long time I thought: most of the items on the symptom list apply to me, so the diagnosis is certain. Yet most of those items are found in nearly everyone who is tired, anxious or sleep-deprived. What makes the distinction is not the presence of the item but what that item has broken in your life.

The practical meaning is this: telling the doctor "my attention wanders" gives little information. "I forgot to pay the same electricity bill three times and the electricity was cut off" gives a lot. The first is a complaint, the second a measurement.

The diagnostic process answers not only the question "do I have it" but also the question "what else could it be."

Differential diagnosis: the most skipped part

Other conditions that could produce a similar picture need to be ruled out:

• Sleep disorders. Sleep apnea and chronic insomnia produce the same symptoms.
• Anxiety and depression. The conditions that most often accompany ADHD, and on their own they also cause attention problems. I covered the distinction in the article ADHD or anxiety.
• Thyroid dysfunction, iron and B12 deficiency. They can be checked with simple blood tests.
• Trauma. Developmental trauma in particular can produce a picture that overlaps with ADHD, and the distinction takes expertise; I wrote about it in the article ADHD or trauma.
• Substance and alcohol use. They directly affect sleep, attention and emotion regulation.

The review by Ginsberg and colleagues shows that ADHD in adults is both under-recognized and that co-occurring conditions are often missed (Ginsberg et al., 2014). In the glossary this step is called differential diagnosis.

One more thing needs adding: differential diagnosis does not mean "either this or that." In adult ADHD, the presence of another co-occurring condition is considered the rule (Faraone et al., 2021). So you can have both anxiety and ADHD, and the two need to be addressed together.

What if there is no childhood history

This is where those diagnosed late get stuck most, and it was so for me too. It is not known whether the report cards survive, not everyone who would remember that period is with you, and what you remember yourself has changed shape through being retold for thirty years.

A few things help:

Look for traces instead of documents. If the report cards cannot be found: old notebooks, teachers' written remarks, notes on the backs of school photographs, even a letter from that period.

One person is enough. A relative, a neighbor, a teacher who knew you as a child. If they cannot come to the interview, a few written answers can also be used in the assessment.

Your own memory is data too. What you remember may not be flawless, but it is not worthless. The clinician is not looking at a single source anyway; they look for a consistent pattern.

Say what is missing. Saying "there is no one who can confirm this period" is not an obstacle in front of the process; it lets the clinician give more weight to other data.

Preparing before you go

The interview is short, and in ADHD there is a lot to tell. Preparation that helps:

• Writing down concrete examples of where you struggle (a missed appointment, a job left half done, a forgotten bill)
• Noting what you remember about childhood and, if possible, asking family
• Digging out old report cards and teacher comments, if there are any
• Listing all the medications and supplements you take
• Noting your sleep pattern for a few weeks

Write three scenes. Prepare three concrete scenes from your childhood and write beside each one: how old you were, where it happened, who was there. Saying "I was absent-minded" is one thing; saying "in sixth grade I lost my homework notebook three times, and the third time the teacher called in the family" truly makes the clinician's job easier. Doing this preparation took me one evening and saved half of the interview.

How long the process takes

It may not finish in a single interview. It is normal for it to be spread across two or three sessions; a blood test or an additional assessment may be requested for differential diagnosis.

A long process is not a bad sign. A diagnosis made in a single short interview, looking at only one scale, deserves a second opinion.

About online tests

Short screenings are designed to sort out people who may be at risk. A high result is not a diagnosis; it is a reason to go for an assessment. A low result does not rule out ADHD either: screenings often miss people, especially those who mask and those in whom the inattentive type predominates. I covered what these tools can and cannot do in the article are online ADHD tests reliable.

Some of the lists on social media are accurate, and some are general enough to fit anyone. A description feeling familiar to you is not evidence on its own.

After the diagnosis

What I expected did not happen. The feeling of "now everything is explained" lasted a few days, and then gave way to something else: anger about why those years went the way they did. It turned out this had a name and was normal; I wrote about it in the article grief after diagnosis.

A diagnosis does not remove responsibility. It changes how that responsibility is carried, and I think that is what really makes going through the process worth it.