You have been through two bad things in your life. One you can describe at a dinner table, in order, without your hands doing anything unusual. The other one has your sleep, and you couldn't explain why it's that one and not the other.
That question is a useful place to start. What causes PTSD is partly the event and largely everything around it: what was happening inside you at the time, whether there was any way out, and what the following weeks were like. Two people can go through the same night and come out with very different odds. This article looks at where PTSD shows up, then at the causes. Reading about it isn't a diagnosis, and nobody gets one from the internet.
In your body first
Most people notice the body before anything else. The alarm system that should fire in danger stops telling the difference between a threat and a reminder of one. A door bangs in another room and you're on your feet.
Sleep is often affected early. Falling asleep takes a long time, waking is easy, and nights break up in ways that leave you tired in a way sleep doesn't fix. Then there's the baseline: braced shoulders, an aching jaw, a stomach that reacts to everything, a sense of scanning that never fully switches off. Some people feel the opposite as well, a numbness or flatness, as if they're watching the day rather than living it.
Reading has its limits. A free 15-minute consultation often moves faster than another dozen open tabs, and it asks nothing of you beyond the fifteen minutes.
In your thinking
The defining feature isn't that you remember what happened. It's how the memory behaves.
Ordinary difficult memories stay in the past. This kind arrives uninvited, in fragments, and feels like it's happening now. A smell, a sound or a flash of image, and your body responds as if it were then.
Memory can also have gaps, or an order of events that won't stay fixed. Beliefs often settle into a few shapes: that it was your fault, even when nothing else was possible; that the world isn't safe; that you can't trust your own judgment; that you're permanently different now. Dreams belong here too. They aren't always replays. Often they carry the same feeling in a completely different setting.
What does PTSD do to the brain? Put simply, under enough threat, the brain may not finish its usual filing. Most experiences get processed and put away as finished. This one doesn't, so it stays live, and reminders keep triggering a full physical response. That's why knowing you're safe doesn't fix it. That isn't a failure of intelligence or willpower, and it's the part trauma-focused therapy is designed to work on.
In what you do and avoid
Avoidance keeps PTSD going, and it's also a very understandable response.
The obvious version is places and people: not taking that road, not going back to that building, always sitting where you can see the door. The quieter version is internal: staying busy so there's no quiet, steering conversations away from the subject, drinking in the evening to get to sleep. Avoidance works in the moment, and that's the problem. The relief tells the alarm that avoiding is what kept you safe, and your life gets a little smaller each time.
Some of it looks like the opposite, like risk-taking or working eighty hours a week.
Relationships feel it too. Irritability is often what others see first, because a nervous system running flat out has little left for everyday friction. Then comes distance, and the certainty that nobody who wasn't there could understand.
What PTSD is not
It isn't the normal reaction in the first weeks. Almost everyone who goes through something terrible has a stretch of broken sleep, jumpiness, replaying and numbness. That's an expected human reaction, and for most people it eases as the weeks pass.
It isn't limited to combat. It shows up in paramedics and nurses, after assaults and collisions, in refugees and in parents after a frightening birth.
It isn't a measure of how bad the event looked from outside. What counts is what happened inside you during it.
It isn't a weakness of character, and it isn't permanent by definition. You also don't have to prove you deserve help before you reach out.
How is PTSD different from a normal stress reaction? Three things. Direction: a normal reaction generally improves over the weeks, with bad days inside a better month, while PTSD holds steady or gets worse. Interference: when the response starts taking things off your list, and the list keeps shrinking, that's different. And presence: in a normal reaction, the event feels more and more like something that happened. With PTSD, it keeps behaving like something that's happening. If you're a few weeks in and unsure which you're in, that's reason enough to talk to someone.
What causes PTSD, ingredient by ingredient
Does everyone who goes through trauma get PTSD? No. Many people have a hard few weeks or months, then find the symptoms gradually ease. If it stayed with you and not with someone standing next to you, that says nothing about either person's strength. The ingredients were different. There's no single cause. Several things stack up.
What the event was like. Events involving deliberate harm by another person tend to be harder to recover from than accidents, especially when someone who was supposed to be safe was involved. So are events that were prolonged or repeated, or where escape wasn't possible.
What happened inside you at the time. If you went numb, felt unreal, watched from outside yourself or froze, the experience may have been more likely to be stored in that unfinished way. Freezing is an automatic response, not a choice, and people often blame themselves for it for years.
What happened afterward. Being believed, having someone to tell, being able to rest, and whether the danger actually ended all matter a great deal. Support after the event is one of the few factors anyone can influence, which is a strong reason not to carry it alone.
What you brought with you. Earlier trauma, especially in childhood, and earlier depression or anxiety can raise the odds. None of this is destiny or a flaw.
What else was going on. The same event lands differently in a year that already held a loss, a separation or money trouble.
Can PTSD start years after the event? Yes. Clinicians recognize a delayed pattern. Often something has changed, like a new loss, retirement or a calmer stretch of life. A late start doesn't make it smaller. It often means a strong coping system finally ran out of room.
Symptom groups and labels you may see
Clinicians group PTSD symptoms into four areas: intrusion (memories, flashbacks, nightmares), avoidance, changes in thinking and mood, and changes in arousal and reactivity, like startle, sleep and irritability. Some people mostly feel numb and detached rather than frightened, which can lead them to wrongly assume they can't have PTSD.
Complex PTSD describes what can develop after prolonged, repeated experiences where leaving wasn't possible. Our article on complex PTSD vs PTSD explains the differences.
Getting assessed and getting help
At our practice, psychologists and Nurse Practitioners can assess and diagnose. Our Nurse Practitioners, who see clients in Kitchener, Waterloo and Cambridge, can also prescribe medication when it's needed. Our Registered Psychotherapists and Registered Social Workers provide therapy. You don't need a diagnosis to start therapy.
Treatment doesn't have to begin with telling the story. The usual path is building stability first, then working on the memory if and when you're ready. You can read about what happens in an EMDR session or see how we approach trauma and PTSD counselling. If you're already taking medication and something doesn't feel right, raise it with your prescriber or ask about our Nurse Practitioners, and don't stop anything on your own.
If any of this has been sitting alongside thoughts of suicide or hurting yourself, please reach out today rather than waiting for an appointment. Our practice can't offer crisis support. Call or text 9-8-8 any time. In Waterloo Region, call Here 24/7 at 1-844-437-3247. In Ottawa, call the Mental Health Crisis Line at 613-722-6914. If you're in immediate danger, call 911 or go to the nearest emergency department.
Taking the first step
You won't need a referral, and we don't have a waitlist. We've been part of Kitchener-Waterloo since 2016, and we see people in person in Waterloo, Kitchener, Cambridge and Ottawa, or online anywhere in Ontario. Sessions with our therapists are $130 to $200, and there is a one-time $50 setup fee. Sessions with our student therapists are $0 to $80. Many extended health plans cover counselling, and in many cases we can bill your insurance directly, depending on your plan and your therapist. Depending on your plan, your insurance may cover the full session fee.
If this has been at the bottom of your list for a while, a free 15-minute consultation is a small way to move it up, and you decide what happens next.