I was diagnosed privately as an adult (in an actual in-person clinic, if that matters) by three professionals with decades of NHS diagnostic experience between them.
It absolutely wasn't just on the basis of self reported symptoms.....my husband submitted very detailed written information and completed various lengthy questionnaires, I provided statements from friends and relatives relating to childhood and also evidence from years ago from my school. There was also the direct observation of my behaviour during the assessment sessions (yes, multiple).
I am also currently awaiting NHS assessment for related /commonly co-occurring types of neurodivergence, and have many relatives diagnosed with autism and ADHD on the NHS, if that helps to convince anyone that I didn't just make this all up for benefits or as an excuse for being a bit mediocre (I unfortunately feel the need to say that after reading many responses in here!
Private clinics charge a lot of money and also in my experience have screening tests/initial introductory appointments before someone is put through for a full assessment.... is someone gets through the initial screening and is prepared to pay up to £2000 for the assessment (not for the diagnosis!) then of course there is a very high likelihood of the diagnosis being given....they must be pretty certain to pay so much and there must be enough evidence to get that far. The experience was also DRAINING and very soul-destroying......I can't imagine anyone wanting to go through it if they didn't really feel the need to!
My reason for wanting a diagnosis, for those who have wondered (and it is a diagnosis and NOT a label FFS!) was to save my life, frankly! Older close relatives have died way before their time directly due to what was SO clearly undiagnosed ADHD......impulsive, risk-taking behaviour, additions due to self medication with other substances..... my own life was starting to increasingly spiral and I genuinely felt I was starting to go the same way they did. I was aware by then that various relatives of mine had been diagnosed (several on the NHS) and the genetic links and similarities to myself and my own struggles seemed blindly obvious.
I was born in at a time when there was absolutely no hope of being diagnosed as a child (as a girl especially!) but in hindsight it is just so, so obvious. I was just given a whole load of other negative labels as a young child, rather than my correct diagnosis, and I'm sure many women of a similar age have experienced the same thing.... hence many people looking into assessment now (especially if their children start getting diagnosed).
I genuinely believe the medication is life-saving for me, and no I wasn't prepared to wait four plus years on the NHS for it (which was what my GP told me the wait would be) in case my ADHD killed me in that time! I'm not being over-dramatic there either.... the impact on ADHD (undiagnosed/untreated especially) on life expectancy is grim stuff, as seen clearly in my own family. I am quite prepared to wait for assessments of wider, related neurodivergence on the NHS, because that doesn't threaten my health and wellbeing in such a similar way.
Threads like this make me feel so upset and embarrassed to share my private diagnosis with anyone, as there is clearly SUCH a lot of judgement and misinformation. One day I might learn not to click on such things, as they can be SO upsetting to read (emotional dysregulation can be a massive part of ADHD, along with rejection sensitivity)....
I won't be able to cope emotionally with coming back to read any replies, so PLEASE nobody response and tag me.....I just felt that I had to at least try and tackle some of the rampant disinformation and judgement that I have read here......