I know I spend a lot of time talking about autism and ADHD in this comm so I wanted to make an effort to spread the focus a little and talk about how PTSD and ADHD can feel very similar and where symptoms can overlap, with a focus on PTSD and the internal experience of it. In talking about PTSD there's necessarily going to be a big

[CW: Discussions of trauma and abuse, mostly from an abstract perspective or an internal experience]

I'm going to rely a lot on this fight/flight/freeze/flag/faint curve. This isn't perfect and it's not definitive but it'll do:

It's worth noting that this is the typical curve but you may not find that you progress linearly through the spectrum, you may cycle very quickly through the first stages or you might just instantly switch to one of the latter phases. This is not uncommon at all.

So with PTSD it's really common to experience hypervigilance. This is when you are in a state where your mind goes into threat-detection mode and you become extremely attuned to your environment, often to the expense of other considerations including things like your biological needs. Hypervigilance is closely associated with the fright part of that curve diagram but it also happens in the freeze, fight and flight parts too.

This experience of hypervigilance might be for 10 minutes, it might be for days. Hypervigilance associated with PTSD grips you like a vice. For me it feels like my sense of time recedes as I become so acutely aware of every little sound, every little change in my environment that nothing else even registers as a concern. Hypervigilance is usually triggered by external environment - a door slamming, a car backfiring, a person yelling or screaming. But it can also be triggered by internal experiences emotional states or thought patterns or recalling memories, especially in cases of CPTSD. Hypervigilance can look a lot like ADHD inattentiveness because your ability to regulate and direct your attention is overridden by a survival and self protection instinct. You might be in the middle of a conversation and notice a person out of the corner of your eye who resembles an abuser and suddenly it feels like you've zoned out completely. Or maybe it sounds like someone is walking up behind you and your brain immediately devotes all of its attention away from what someone is saying to you and towards detecting and responding to this potential threat that is approaching.

Dissociation is another common experience of PTSD. This is associated with the far end of the spectrum, from flag to faint (imo there needs to be a fawn between those two points but I'll try to elaborate on this later in the post).

Dissociation feels very checked out and disconnected from anything. For me it feels like my head is under water - things still register but everything feels very muted and distant. I stop feeling things in my body. I often need to have prompts or stimuli multiple times before it registers in my brain that I need to respond. This might be the classic, almost-ADHD situation where a person needs to click in front of your eyes and say "Hey... Hey! Are you even listening??" or it might be a timer or an alarm going off for a solid 60 seconds before that sound connects to the I'm supposed to respond to this stimulus with an action thought process.

Both hypervigilance and dissociation can bring with it the impression that you have a sensory sensitivity that can resemble ADHD or autistic traits. You may find yourself in an extremely uncomfortable situation physically but this doesn't really register in your awareness until it manages to burst through the hypervigilance or dissociation where you suddenly feel the overwhelming need to address this situation. The same thing happens with other biological needs besides the sensory, such as hunger and tiredness. With PTSD you may not register your tiredness or hunger (or the need to pee or feeling uncomfortably cold or any other biological need for that matter) until it is bordering on an emergency.

This can feel like poor interoception or like sensory sensitivity. The difference between autistic or ADHD traits and PTSD symptoms here is that a person will only experience these things some of the time, during periods of abnormal psychological states; I'm autistic - I always hate the feeling of velvet and velour, and I always have. When I'm struggling with my own PTSD symptoms and I'm hypervigilant or dissociated, I can lose connection with my physical experience and I can fail to notice my physical discomfort until it starts becoming excruciating, at which point I respond. But this is not my baseline experience. I have always hated rough wool and been unusually sensitive to it, throughout my entire life, because I'm autistic. I sometimes don't register that my skin is itchy due to hayfever until it feels like my skin is on fire because PTSD symptoms make me check out from my internal experience. (Hopefully that helps make a clear distinction between the two experiences where they appear to overlap.)

With PTSD, after the peak comes the inevitable crash. For example, if you're hypervigilant or in a state of flight for a long period then a crash is inevitable as your brain and body cannot sustain this heightened state permanently.

The hangover from these PTSD symptoms feels very similar to executive dysfunction. Maybe you were hypervigilant and barely slept a wink last night, you were too anxious to eat much, and now your brain is fried from the psychological state alone without even mentioning the impact of your blood sugar being a disaster and the impacts of insomnia on yourself. Or maybe your day has been one triggering event after another and you've been putting a huge amount of effort into keeping it together and you're just mentally drained from the constant strain. This is by all measure the exact same as executive dysfunction and it would be borderline impossible to tell the difference between typical ADHD executive dysfunction and a PTSD hangover (not a legitimate term btw, just one that makes sense to me and which doesn't feel inherently pathologising). The difference is in what caused this experience - with ADHD or autism, it's the consequence from trying to focus, dealing with sensory overload, masking and stuff like that. With PTSD there should be a very clear triggering event and a heightened psychological state that directly preceded your brain turning to mush temporarily as you recover.

The last big thing that comes to mind is that it's common for people who experience PTSD to go into fawn mode. This is particularly common in CPTSD and afab peeps.

Fawn roughly comes between flag and faint on that curve above. The fawn response feels very similar to masking, to the point where there's a discussion to be had about whether autistic people pleasing/fawning is itself a direct response to social rejection and trauma due to socialising, but that's something for a different post.

The fawn response is where you become extremely compliant, where you lack appropriate boundaries and the ability to maintain them, where you engage in people-pleasing behaviours, and where you attempt to appease others especially where they feel like a threat (this doesn't mean they are towering over you and making threats against you, it may be a particular type of person who fits closely to an abuser's characteristics, it may be an authority figure, it may be difficult to identify what about someone tells your brain "This person is a threat!!"). Conflict avoidance and codependency are super common in the fawn response, and out of the spectrum above I'd argue that the fawn response is probably one that is much more difficult to identify since it can feel very similar in the level of arousal as what is more or less typical and since it is the most sustainable over a long period of time, at least in my experience.

The fawn response, to me, is one where I find myself entirely focused on the emotional state of others without any connection to my own emotional state or beliefs (think principles, morals, ethical positions etc.) A person in a fawn response state might find themselves laughing at a racist joke, agreeing with a reprehensible opinion, or a violation of their bodily autonomy, in contradiction to their own values, because they are instinctively trying to avoid coming into conflict with another person by being assertive and maintaining boundaries, although this is just an example of the many ways it can manifest. How do you tell the difference between PTSD fawning and autistic or ADHD masking? That is a complicated question and it's very tricky.

As a general rule, a person who experiences PTSD will only experience this state intermittently and often as a response to identifiable threats but, because of the ability to sustain a fawn response and because it's kinda pernicious rather than being extremely obvious like the other states, this is only a rough guide and it may take a lot of work to figure out when you're experiencing the fawn response and how to identify the signs of it.

To conclude the main part of this post, those with PTSD you should find over time that the symptoms generally become diminished (with a strong caveat that sometimes processing trauma can make other stuff bubble up to the surface, making it feel like you're doing worse or going backwards, and sometimes you can bring about a sort of healing crisis as you bring old traumatic experiences to a head). With ADHD or autism, often the more you process things the more you become aware of your inherent traits like executive dysfunction, masking, people pleasing and so on. But they tend to be much more stable and persistent across (mostly) your lifespan whereas PTSD has a clear demarcation before and after the traumatic event(s), although of course CPTSD is the confounding factor due to the fact that it in particular is associated with early and developmental trauma so it's not always possible to remember back to a time where there was a "before", and for many survivors of child abuse there actually isn't even a "before" (with some pretty clear evidence that traumatic experiences in utero can produce PTSD symptoms in children after being born).

So hopefully this helps to clarify things for you if you're trying to understand what you're experiencing or the ways that PTSD and ADHD (and in some respects autism) can seem to overlap. I know I haven't paid any attention to when they co-occur and this is because it's an extremely complex matter and it would take an entire post in itself to cover this (although I'm not sure if I'd be able to do that subject justice tbh).

Just as a final passing thought, I think that a key strength of the neurodivergence umbrella is that for example, due to the significant overlap in experience of these different conditions, PTSD survivors may find a lot to be gained by borrowing from insights into sensory modulation and dealing with poor interoception coming out of the autistic part of neurodivergence (research, theory, and self-advocacy) and autistic people might likewise find there's a lot to be learned from managing people-pleasing and the fawn response from PTSD survivors. Of course there's a lot more that we can learn from one another too but that's the most obvious examples that spring to mind.

(Turns out that I ended up talking about autism more than I anticipated. Oh well.)