ODD – deficit or injury to the brain, genetic personality trait making them more prone to having ODD or environmental
PDA – genetic
ODD – may have autism/Asperger’s as well, although some believe autistic people cannot also have ODD as those types of traits are common in autism difficulties anyway
PDA – a sub-type of autism so will have autistic traits anyway. You cannot have PDA without also having autistic traits although PDA traits may mask autistic traits
ODD – may have anxiety as a symptom, will only experience anxiety in certain situations
PDA – will have anxiety as a characteristic, will experience anxiety nearly all the time
ODD – will accept and even improve behaviour for praise
PDA – won’t accept praise and praising may make behaviour worse
ODD – behaviour improves with strict routine and boundaries
PDA – strict routine makes behaviour worse and will usually only accept routine created by themselves, boundaries are either ignored or make behaviour worse
ODD – explaining rules will improve compliance of said rules, but not always
PDA – explaining of rules may improve compliance but may also create more anxiety
ODD – springing changes on them may cause a negative reaction
PDA – springing changes on them may help them accept change easier
ODD – giving plenty of warning should see positive reactions
PDA – giving plenty of warnings may see a more positive reaction or may see a negative reaction because anxiety has been allowed to build up
ODD – the same tasks will receive the same response every time
PDA – the same tasks may have a different response each time because the anxiety of the person changes from day to day
ODD – can understand why respect for authorities is important but may still be disrespectful
PDA – will not understand why authorities should be respected regardless of actions and may be disrespectful unless the authority has been respectful first
ODD – may refuse to do something because they don’t want to or because they feel the need to refuse
PDA – may refuse to do something for a reason, anything from sensory issues, not understanding task, time restraint creating anxiety, anxiety, difficulties with transitions, etc
ODD – rarely will refuse to do something they want to do
PDA – often will refuse to do something they want to do because their anxiety or other issues make it too hard for them
ODD – respond to time limits, routine charts, reward charts and other positive behaviour techniques
PDA – may respond for a short time or may not respond at all to positive behaviour techniques
ODD – behaviour may be consistent in all environments or different depending on the person they are with
PDA – behaviour may be consistent in all environments or they may mask in certain environments, regardless of who they are with
ODD – will generally not have panic attacks or show anxious behaviour
PDA – will show anxious behaviour and may have panic attacks
ODD – reducing demands usually makes behaviour worse
PDA – reducing demands usually makes behaviour better
ODD – if left to their own devices will usually not complete necessary tasks such as eating and tidying up
PDA – if left to their own devices may complete necessary tasks by themselves
ODD – don’t want to be ‘good’ but want praise and attention
PDA – want to be ‘good’ but may not want praise and attention
ODD – may have some social issues, but this wont be based in communication struggles, needing control of situation, lack of boundaries etc. May make and keep friends easily depending on behaviour. Will be subject to peer pressure
PDA – social issues usually associated with communication struggles, needing control, lack of boundaries etc. May make friends but will struggle to keep them regardless of behaviour. Will usually refuse to give in to peer pressure
ODD – will usually use negative behaviour to get out of doing tasks, many of which are aggressive and violent
PDA – will usually use a range of tactics to avoid tasks, many of which are non-aggressive and non-violent, however if pushed many may resort to violence due to the increase in anxiety
ODD – generally do not have panic attacks when their behaviour is challenged or when strict discipline is used
PDA – may have panic attacks when pushed or faced with strict discipline. Panic attacks are when their anxiety has become so high they are unable to regulate their emotions, panic attacks can often be violent and are similar to a meltdown, when in this state the person has lost all control
ODD – will usually be consistent in their personality behaviour
PDA – will display ‘Jekyll and Hyde’ behaviour
There are many similar behaviours and traits with ODD and PDA, however there are some which are unique to each diagnosis. Basically, if there are no autistic traits then you’re looking at ODD. I doubt you can have both, some may disagree.
All these points are my opinion generated from my own understanding and gleaned from various articles. As such the information may not be 100% accurate (then again what is?). If you disagree with anything in this post then please feel free to message me 😀
Riko's blog: PDA and more. 
What an amazing insight you share. Thank you.
hi my son had diagnosis of ODD when he was 4 put on metatolin to settle sleep as the drs had in mind adhd now as they have done numerous of tests and 5 yrs on i have diagnosis of ASD Apergers PDA and ODD is still there as this was earlier signs there was problem yet his meltdowns there is no talkin him round its like he loses all his senses as sometimes hes banged his leg or head or hurt himself in some way and its not until meltdown is over he reconizes it then its everybodys fault right from young age hes says dont talk to me like child yet he is and still is child lettin him be line monitor helped for awhile but 2 kids were naughty so he banged there heads together he took authority too far my question really is how can they put both in diagnosis should i be questioning it as PDA is rarely reconized by drs in my area it was actually pyschartrist who seen my son in full form that said he has PDA and after watching him for further year all 6 proffesionals said same by this time he been thrown out of school as he had no regard for head teacher
It might be worth questioning the ODD diagnosis, especially if it will affect the help and accommodations he gets. They tend to use strict discipline with ODD which will make PDA worse. The not recognising being a child and wanting to be in charge are PDA traits. We find that during meltdowns there’s no rationalising with the person, there seems to be a cut off point and after that nothing will register. After a meltdown many kids won’t remember what happened. In his mind he might blame everyone else because he may rationalise that if they/you weren’t there then he wouldn’t have had a meltdown, whilst there may be some element of truth to that he also can’t avoid every trigger for meltdowns. Usually finding out what causes them and finding ways for them to learn to manage meltdowns helps. For PDA kids this is much harder because anything can be a trigger, and what may be a trigger one day may not be the next. You said he now has a diagnosis of PDA and others, I would think they would override any previous diagnosis. Could you speak to the person who diagnosed him and ask for ODD to be removed? I’m presuming any strategies tried for ODD didn’t work? so removing it would make sense.
Thank you for this, I was unsure of the difference even though I’ve been told my son has all PDA traits by his keyworker, unfortunately they don’t officially diagnose where I live, but will hopefully receive some kind of diagnosis in the next couple of months, just in time for him to start school.
Hi,
I’m not sure it’s true, but I have read (on various sites) that PDA children naturally reject and can’t stand constraints, social rules, hierarchy and demands emerging from other children (and especially from the GROUP of other children, who have their own internal social norms and games) AS WELL as from adults,
while ODD kids would basically reject adults’ authority but fit in the social rules of the children’s groups.
What do you think about this idea ? Does it seem right or wrong to you ?
I think some PDA kids struggle with the rules and demands from other kids, but those of us who mask might not.
I know as a kid I would just follow the other kids around and do whatever they did and said.
I’ve heard of other PDA kids being similar, to the point that they do things they know are bad or don’t actually want to do, simply because other kids have told them to.
The need to fit in and not be seen as different can be overpowering.