What happens in an adult ADHD assessment

Assessments usually last from one to several hours and may be split across visits. They are carried out by a psychiatrist, psychologist, specialist nurse or other trained clinician. Most include a structured or semi-structured interview, questionnaires completed beforehand and, ideally, information from a parent, partner or old school reports.

• Attention, distractibility, losing things, forgetfulness and difficulty finishing tasks.

• Restlessness, impulsivity, interrupting, and difficulty waiting.

• How these have affected school, work, relationships and finances.

• Childhood behaviour, school reports and any previous assessments.

• Sleep, mood, anxiety, trauma, alcohol and drug use.

• Medical history, medicines and family history of ADHD or related conditions.

Many services use a structured interview such as the Diagnostic Interview for ADHD in Adults, which walks through the diagnostic criteria with examples from childhood and adulthood. Rating scales completed by you and, sometimes, another person provide further information. Some services add computerised attention tests, but these cannot diagnose ADHD on their own. NICE guidance emphasises a full clinical assessment rather than reliance on any single measure.

A good assessment considers other explanations for similar symptoms, including anxiety, depression, bipolar disorder, post-traumatic stress, autism, sleep apnoea, thyroid disease and the effects of medicines or substances. Because stimulant medication can affect the heart, the clinician will ask about cardiac history and family history of sudden cardiac death, and will measure blood pressure and pulse before treatment. Blood tests may be requested if medically indicated.

The assessor should explain whether you meet criteria for ADHD, what other conditions were identified and what treatment options are available. You should receive a written report. If you are not diagnosed, you should be told why, and what else might help. If you are diagnosed, they should discuss medicines, non-drug support and how to access them.

Gather school reports if you have them, note examples of difficulties at work and home, and ask a close relative if they can contribute. Make a list of medicines and previous mental health diagnoses. Be honest about difficulties and about strengths, because a balanced picture is more useful.

People often worry that they will be disbelieved, that they will forget important details or that a diagnosis will be refused because they have managed so far. Assessors are used to these concerns. They know that many adults compensate and that memory of childhood is imperfect. If you feel that something important was not covered, say so before the end and ask whether you can send additional information in writing afterwards, such as school reports found later or comments from a relative.