Adults who suspect ADHD, often after recognising it in a relative or a child, usually want a realistic timeline before committing to the process. Between the referral letter, the intake and the assessment itself, the total is counted in months rather than weeks, which changes how work, study and treatment plans get arranged around it.
Budget for months, not weeks — that's the honest starting point. After your huisarts refers you (the verwijsbrief needs to document a genuine suspicion of ADHD, not just a general request for assessment, so a thorough GP conversation beforehand matters), you join a GGZ waitlist that commonly runs several months to over a year before the actual diagnostic assessment happens, on top of whatever wait exists between referral and first intake. Adult ADHD diagnostics aren't triaged as urgent in most instellingen, so they tend to sit toward the back of an already long GGZ queue. If the wait is unworkable, two things help: ask your insurer's wachtlijstbemiddeling to place you somewhere with shorter lists, and register with more than one provider simultaneously since nothing stops you doing that while you wait. Private, self-pay ADHD diagnostic clinics exist and move much faster — often weeks rather than months — but expect somewhere in the €1,000–2,000 range out of pocket for a full assessment, since it's not reimbursed unless the clinic is contracted with your insurer. If you were already diagnosed abroad, bring the full report; some psychiatrists will do a shorter confirmatory assessment rather than starting from zero, though that's decided case by case, not guaranteed.