He thinks it's all just anxiety.
Like, wha!?
Both can trigger a response from your autonomic nervous system in similar ways.
But whereas a panic attack is the straight up flight/fight/freeze response, a flashback (which may trigger that same response) comes with re-experiencing the traumatic event (one of the core types of symptoms that define ptsd).
You may have a panic attack when having a flashback, but not necessarily.
With panic attacks, something that was helpful to me was learning to keep track of my SUDS throughout the day. Panic attacks often feel like they've come out of the blue, but most often the stress levels have been increasing prior to hitting the panic.
SUDS (Subjective units of distress) is basically "How stressed am I right now?", based on your own subjective experience. Monitoring that, you'll get to know what's normal for you. You might wake up at 2 out of 10, then get a difficult phone call and notice your distress levels shoot up to 6, and then something else stressful happens and you're at 8.
A panic attack is what it feels like for you when you hit 10 out of 10. So, keeping check of your SUDS, you can intervene earlier (like when you hit 7 or 8), and do whatever it is you do to bring your distress levels back down. That will massively decrease the likelihood of having a panic attack.
It takes practice, but for people who get regular panic attacks (like I used to), it can be a real game changer learning to check your SUDS levels throughout the day, and intervening when you notice them going up.
For a typical panic attack? The easiest way to force your physiological response out of panic is to use controlled breathing. And there's lots of different ways to practice that. Practice it daily. Like any emergency response, you don't want to be trying it out in an emergency, you want to get pro at it during calm situations so that when you panic, it's an easy and natural way to get yourself out of it.
Controlled breathing forces that neurological response to change - heart rate, hormones, blood pressure, circulation, switching organs and systems back on.
With practice? Controlled breathing has got me to the point where I very rarely actually reach panic level (because I intervene when my SUDS are getting too high), and it means that when I have had panic attacks, I no longer pass out or wet myself (extremely liberating). But I practice my breathing Every. Single. Day.
Flashbacks are a re-experiencing symptom. Your amygdala thinks that your trauma is happening again. So it may trigger that same fight/flight response, but the key to getting out of it is usually grounding techniques (different for everyone). Grounding techniques are the ones that bring your mind back to the present, where the trauma isn't happening again, and your brain can put it together that this is 2019, not "when the trauma occurred".
Controlled breathing can help you ground, but grounding techniques tend to be different. There's a whole tonne, and it's about finding the right grounding technique for you.
But like controlled breathing? Grounding techniques are something you practice daily, when you're actually feeling okay. So that when something triggers a flashback, the grounding technique that is helpful to you comes easily and naturally.