Do take a look at the sites I mentioned. For someone with ADD - not ADHD - this stuff happens all the time. I think the question is, in a normal interesting discussion (when they seem to be paying attention), do they seem slow to you. Or when they are discussing something that they are interested in (not you), do they seem slow? If they are able to carry on an intelligent discussion, then something like ADD is very possible. If they can't, then ya they could be "slow". So what, they are a friend, and I assume they are a friend for reasons other then their IQ.
By the way, anxiety and depression are very common for adults with undiagnosed ADD. Hope this helps.
This friend is 27. and ive known them 4 about 5 or 6 months. they said they failed 9th grade twice i think. so im thinkin this person has always ben slow. i have noticed that my friend gives the most puzzled and confused looks and when i ask them why the puzzled look? they reply i didnt know i looked puzzled. random hysterical laughter. 4 no apparent reason. tantrums so bad that tears come to my friends eyes over the smallest things. and random statements that make no sense.
How old is your friend? Has s/he always been this way? Does this friend have many other friends? I am ADHD but catch on to humor and process, too fast than slowly. Yes, both ADHD and ADD individuals may appear to be slow processors because they are distracted easily or hyperfocused on something else. Sometimes, however, people can be very literal thinkers and may not understand the language that come with jokes and figurative speech. This could also be a result of being a visual learner instead of an auditory learner, too. Also, people with high level Asperger's can be like this. More infomation woluld needed, as Sandman2, states above. The most important thing is whether your friend has always been like this. If not, I would be talking with the counselor at school, or his parents, if you feel comfortable in talking to them.
It isnt drugs i know this person well. than you very much 4 ur response
A person with ADD can have trouble focusing and paying attention to something that is not stimulating to them. So in that sense it is possible. But many ADD people have a very fast train of thought, if the interest level is there.
Two sites aimed at the adult ADD sufferer that you might want to check out are totallyadd.com and http://jeffsaddmind.com/for-first-time-visitors. These should give you enough information to help you decide. Honestly, from the short description you gave, I could not say if it was ADD, drugs, stress, etc.