I was diagnosed with ADHD a few years ago when I was 30.
I tried a few medications. When I as on Vyvanse, I noticed similar personality changes as what you described. Most notably, my sense of humour suffered. (And before on dexamphetamine, I was really grumpy when it wore off. So I did get into fights.)
Things got better after I changed to methylphenidate. For me, it's milder in the side effects.
Modafinil and nicotine patches also work reasonably well with only mild side effects. (See https://www.gwern.net/Nicotine about nicotine. Please don't start smoking.)
Caffeine never worked at all for me. Just messed with my sleep. L-Tryptophan seems to help me very slightly, but I have friends who report great effects, especially with sleep and mood.
Enough ranting, my point is: you can try different stimulants to see if there's anything else that works better for you.
Finding the minimal dose that still works is of course still a good idea.
What was the diagnosis process like? I'm in my early 30s and have been putting off trying to get an ADHD diagnosis (and medication) even though the symptoms clearly resonate, because I'm concerned that I'll be dismissed as just seeking pills. In college I tried to get diagnosed and was dismissed as lazy and just seeking a prescription. Did you have to deal with any of that skepticism?
In the United States, there are controlled substances, and federal law requires that a psychiatrist write a new prescription every month, with no automatic refills.
However, it is heavily streamlined. My university medical center and on campus pharmacy had me in and out with a week supply of adderall in about two hours. There were weekly followups for about four weeks, then monthly followups every three months, and then it was just five mins with a psychiatrist for minor adjustments thereafter. After graduation, most psychiatrists will do monthly followups over the phone, and may only require you to come in a few times a year.
I have however heard it can be much harder if they suspect that you are unstable or "drug seeking". But if you don't appear to be a risk, and you can clearly explain your situation, then they will usually offer you a week supply and you report if it helps you. I think a big factor is just what your life situation is.
Private psychiatrists are much more likely to help you. Make an appointment with an "ADHD specialist". As long as you don't have any red flags, they are likely to give you a test prescription"
If you can afford it, go to a specialist (ie Seattle's Hallowell Todaro ADHD Center). It will probably be more expensive and might take longer to get evaluated, but you'll be taken seriously and it's easier to advocate for yourself and your medication when the medical providers don't automatically jump to "pill seeking".
I'm not sure about my current provider, but the place that diagnosed me would let patients complete evaluations at a slower pace if they couldn't afford everything right away.
Also, before I switched to a specialist after moving, I tried asking my GP for my RX and they went straight to "pill seeking", however, they would still allow me to get my script if I came in every month for a drug test.
I was lucky that I was living in Australia at the time where adult ADHD seems to be taken more serious by shrinks than in most other parts of the world. I also splurged and saw the shrink privately.
So the diagnosis process was mostly answering lots of questions and filling out some questionnaires.
I know that the plural of anecdote is not data, but modafinil can have some not-so-mild side effects.
I have been pretty healthy my whole life, exercise regularly and eat a healthy diet, never had any allergy nor anything alike... until I took (ar)modafinil. After 2-3 weeks of occasional consumption (1 pill every 2/3 days) I started with a mouth full of ulcers (aphthae), which progressed to a full-body rash. Apparently I had Erythema multiforme major, one of the potential side-effects of Modafinil, and honestly it was worrying.
Yes, I have had good experiences with methylphenidate (Ritalin) as well. One thing I noticed is that on adderall I stopped yawning completely. On Ritalin, my body is actually able to signal to me when I'm tired, hungry, etc. The problem is that I had to take ever larger amounts of caffeine to compensate.
I just know that I don't want to be taking adderall when I'm 40.
Yes. I had similar reaction: I was very relieved that I could take a nap on Ritalin. That never worked on dexamphetamine.
Though I also heard from some other people for whom Ritalin has intolerable side effects, but Adderall works.
Honestly for me, if methylphenidate wasn't available, I'd go with nicotine patches and perhaps modafinil instead of dexamphetamine.
Thanks to billions of smokers we a have pretty good idea of the long term effects of nicotine. Eg we know that it protects against parkinsons. (And there are some indications that Parkinsons and ADHD are linked.)
I tried a few medications. When I as on Vyvanse, I noticed similar personality changes as what you described. Most notably, my sense of humour suffered. (And before on dexamphetamine, I was really grumpy when it wore off. So I did get into fights.)
Things got better after I changed to methylphenidate. For me, it's milder in the side effects.
Modafinil and nicotine patches also work reasonably well with only mild side effects. (See https://www.gwern.net/Nicotine about nicotine. Please don't start smoking.)
Caffeine never worked at all for me. Just messed with my sleep. L-Tryptophan seems to help me very slightly, but I have friends who report great effects, especially with sleep and mood.
Enough ranting, my point is: you can try different stimulants to see if there's anything else that works better for you.
Finding the minimal dose that still works is of course still a good idea.