There are parents who ask if their child actually has PDA (Pathological Demand Avoidance Syndrome) because 'they are not violent or aggressive'. They question if PDA fits because their child doesn't physically lash out or meltdown. It seems like violent behaviour is becoming known as a PDA trait.
It's not though, there are many PDA people who have never been and who may never be violent or aggressive. There are many who only become violent/aggressive when pushed far beyond their ability to cope. However since PDA people are constantly at the limit of their coping abilities it may not take much to send them into a panic whereby they will lash out physically. This is known as a panic attack.
It's true what they say about the 'loud' ones getting all the attention while the 'quiet' ones are ignored. The PDA people who react violently are usually the first to get noticed, to get assessed, to get diagnosed and to get help. The 'quiet' ones, the ones who avoid by ignoring or walking away, they are slower to be noticed. The textbooks are usually written around the most violent children. But this doesn't reflect the true spectrum of a condition. It's not surprising then that so many see PDA as a condition which causes violence.
It should be noted that PDA is a condition which causes a need to avoid demands, the avoidance tactics used are so varied, however the majority of avoidance isn't violent or aggressive. Avoidance progresses from mild avoidance tactics like ignoring, walking away, saying 'no' through to eloping, using shock tactics, threatening, until all other attempts are exhausted and they have a panic attack, involving verbal and/or physical violence/aggression. Panic attacks are when the PDA individual cannot hold on to their emotions and fear any longer, at this point they have lost all control and are often unreachable.
Sometimes you can see the lead up, a child may start by making excuses to avoid a demand, when the adult keeps pushing they may try distraction, when that doesn't work they may swear or throw objects to draw attention away from the demand being issued. If that still doesn't work the child may become violent, screaming and hitting as they cannot control their anxiety any longer. A knowledgeable adult may recognise the avoidance tactics at the beginning and start to employ PDA strategies to manage the demand and the child's anxiety before it reaches panic attack.
Not every person will go through the build up. Some might start at the bottom with ignoring but when pushed they may go straight to panic attack, this is because either the PDAer doesn't have any other coping strategies or avoidance tactics or because the build up of anxiety is so quick they move straight to meltdown. Some PDAers have been pushed to meltdown mode so often that they are now no longer able to use most avoidance strategies, they go from nothing to panic attack in seconds when faced with a demand.
There are many PDA people who rarely reach meltdown stage, either because they have learnt to manage their own environment to reduce demands or because the people around them have learnt to reduce demands, reframe demands to be less 'offensive' and they recognise avoidance and know when to allow avoidance or work with the PDAer to find a way around the avoidance.
There are ways to help a person use less violent strategies, by reducing demands and noticing when their anxiety is starting to build and allowing them to use avoidance tactics straightaway. With correct handling, most violent PDAers can become non-violent.
It's important to remember that PDAers have little control over using avoidance, they cannot stop seeing a demand as something to avoid and they cannot control a panic attack/meltdown at all. PDA is a disability, with help a PDA person can learn to manage their avoidance and violence but they cannot completely remove the cause.