I just have to add my two very honest cents to this on my own very hand-on experiences, even though I am only a beginner in diving. I have dived some - not much - and was diagnosed with ADHD AFTER being first certified AND after turning 40.
Needless to say, the condition and the symptoms vary greatly between individuals, and I was both really worried and perplexed by the situation.
I passed all the certifying requirements with flying colors (well, they are easy), except that I used a huge load of oxygen in the beginning. I think spewing trough the tank is very much linked to overt excitement caused by the condition and thus being prone to shallow overbreathing. As I have dived more, consumption has gone to normal. I understand this is quite usual with beginners, and was not worried at the time. This, however, is the point; ppl with ADHD tend to have just normal emotions and reactions except that they are multiplied in volume in comparison to average person.
I am glad to say, however, that I do not "blink" and do not get panic attacks, at least so far, and never have, in any situation above or below surface. I just get more agitated at times. Of course time will tell more; I have only had some very minor situations while diving so far, once having my mouthpiece kicked away by fellow diver and once assisting a slightly panicked diver who had lost his group and was low on oxygen back to surface. Both I handled with calm.
I'm extremely rigorous with pre-dive checklists, and insist this from my partner as well. I have never forgotten anything, and usually make two full checks because I know I might be liable to err and forget.
I always dive with the same partner, my wife. My primary concern with my condition is putting my partner at risk, and we have discussed this fully. She just happens to be a on a medication for a psychological condition as well, so the risk taken is both mutual and consensual.
Needless to say I sign the full medical release every time before taking a dip. I do not take drugs before diving even though I am on a prescription
People have commented in this thread how ADHD would affect cognitive abilities and ability to remember. I have a very high IQ, excellent memory and am able to take directions. No faults there.
Here's the other part that's mostly missing from the discussion so far, then, except from by Calinestes above:
For me diving is immersing myself in a world that is exactly the opposition of the sensory overload that keeps me sometimes fully on the pedal above the surface. It is a world of concentration, focus, directing the attention. It is a world that has just the right amount of information and way less sensory bombardment than everyday life. I find myself being able to keep focus indefinitely and easily. The deep breathing technique helps this as well, it keeps me calm, relaxed and able. In fact this is a technique that is taught to ADHD kids in cognitive behavioural training exercises to control their tantrums.
I would have to say that of all the things I have tried to this age (and there are a lot) Astanga Joga and diving are the ones that to me seem most suitable for my psyche. Both involve a focus on relaxed breathing, have a muted palette of sensory information and are primarily things where you are forced to fully focus on what you are doing just now and here.
That said, everyone is an individual, and all the decisions will have to be made on a case-by-case basis. I myself will be following my own condition very carefully and if it turns out I will not be able to do this, I will stop immediately. I do not want to put my loved ones at risk.
