People with ADHD are emotionally impulsive due to the anterior cingulate cortex not functioning. This comes out as frustration, impatience, repetitive talking and quickly becoming angry.

People with OCPD on the other hand, have a overactive anterior cingulate cortex and this also appears to cause the same problems the ADHD type find.
I say 'appears' because, though the OCPD symptoms are slightly different than ADHD, they can still cause the person with OCPD to appear as ADHD due to their similar difficulties they face. For example, A person with OCPD are typically perfectionists so when they are doing a project they can procrastinate due to the amount of work they feel has to be perfect. If it can't be perfect they won't bother attempting anything. This is the same as the person with ADHD because they both procrastinate however the person with ADHD procrastinate due to their high impulsiveness and the wanting to do something more stimulating.
As you can see, both the OCPD and ADHD procrastinate and this ties back to what am saying about how both disorders can have the same symptoms but both have totally different reasons for their problems.

But the main point am getting at with this is, I feel that I may have OCPD and ADHD or just OCPD. I need help distinguishing the two, so am going to ask you ADHD lot :P if you feel you face these problems from time to time or all the time.


feelings of excessive doubt and caution;
preoccupation with details, rules, lists, order, organization or schedule;
perfectionism that interferes with task completion;
excessive conscientiousness, scrupulousness, and undue preoccupation with productivity to the exclusion of pleasure and interpersonal relationships;
excessive pedantry and adherence to social conventions;
rigidity and stubbornness;
unreasonable insistence by the individual that others submit exactly to his or her way of doing things, or unreasonable reluctance to allow others to do things;
intrusion of insistent and unwelcome thoughts or impulses

ADHD & OCDP Difference
ADHD

not at all obsessed with organization, order, details or anal
undependable
bad with money
fun people
creative, out of the box thinking

OCDP

'owning the truth', what i have is 'The Truth'
doing most things themselves & not trusting others work quality
good with money
not fun people
very formal style, mechanical, not warm person
sticks to conventions
answering questions in great detail
insistence by the individual that others submit exactly to his or her way of doing things
dependable
the ADHD people in the support group are not as perfectionist as me.
excessive doubt and caution


ADHD & OCDP Similarities

rigidity & stubbornness
impulsive
difficulty completing tasks (OCDP due to dissatisfaction, ADHD due to stimulation)
indecisive


That being said
I HAVE THE SAME PROBLEM!!!

Diagnosed by top doctor, taking med & after reading five books on ADHD & collecting 12, visiting support groups. Mother diagnosed ADHD.
i am extreme ADHD:)


Diagnosed by another team of doctors, reading about it. Father OCPD(maybe).
i am extreme OCPD:)


My View 1
It is quite possible both are the same. Just different symptom labelling from researchers in different areas. After been to 6 doctors i have seen all of them referring disorders as their favourites just because they did their final project on that topic. Each convinces me his diagnosis was my only ailment. One even showed me his patients register with him labelling majority of them the same, as if it was a communicable disease which has spread in the area.

My View 2
I have both affecting different areas.
OCPD developed as a reaction to my ADHD. Its a personality disorder. The person becomes extremely cautious & perfectionist because of being ridicule & failures due to careless nature of ADHD. I had very strict parents.

Medication:
I can see OCPD doesnt have a medication just for it. But i am taking methylphenidate for ADHD which has somehow helped the OCPD by putting me in hurried state & makes me do things imperfectly. I feel it is inhibiting me from thinking a lot, which has proven quite bad in complicated situations but quite good on the whole for my life. Presently i need to badly get out of my stagnated life of 'paralysis by analysis' by thinking straighforward but in the long run not being able to think parallely & creatively might hinder me.

The best advice i have found is keep on moving.

I would love to hear from others.