Panic attacks are triggered by a combination of biological, psychological, and environmental factors, and sometimes by substances or medical conditions that mimic the panic response. For many people, no single cause is responsible. Instead, several overlapping factors lower the threshold until something tips the body into a full alarm reaction. Understanding these causes can help you recognize patterns and, in many cases, reduce how often attacks happen.
What Happens in Your Brain During a Panic Attack
A panic attack is your brain’s threat-detection system firing when there’s no actual threat. The part of the brain responsible for processing fear sends urgent signals through ancient survival pathways, flooding your body with stress hormones like adrenaline. Your heart rate spikes, your breathing accelerates, and your muscles tense, all within seconds.
Several chemical messenger systems in the brain are involved, including serotonin, norepinephrine, and GABA (the brain’s main calming chemical). When the balance between these systems is disrupted, the brain’s higher-level thinking areas lose their ability to override the fear response. In simple terms, the rational part of your brain can’t put the brakes on the alarm fast enough, so the panic spirals before you can talk yourself out of it.
Clinically, a panic attack is defined as a sudden surge of intense fear accompanied by at least 4 of 13 recognized symptoms. Those symptoms fall into two categories: physical ones like a pounding heart, chest pain, shortness of breath, dizziness, sweating, trembling, nausea, numbness, tingling, and hot or cold flashes; and cognitive ones like a fear of dying, a fear of losing control, or a feeling of detachment from yourself or your surroundings. Most attacks peak within 10 minutes, though the aftereffects can linger for much longer.
Genetics and Family History
Panic disorder runs in families, and the reason is partly genetic. A meta-analysis published in the American Journal of Psychiatry estimated the heritability of panic disorder at roughly 48%, meaning about half of a person’s vulnerability comes from their genetic makeup, with the other half shaped by life experience and environment. You don’t inherit panic attacks directly, but you can inherit a nervous system that’s more reactive to stress and more prone to misfiring its alarm signals.
If a first-degree relative (parent or sibling) has panic disorder, your own risk is significantly higher than the general population’s. That said, having the genetic predisposition doesn’t guarantee you’ll ever have a panic attack. It simply means your threshold is lower, so the other causes on this list carry more weight for you.
Life Stress and Trauma
The most common trigger for a first panic attack is a period of intense or accumulating stress. Major life disruptions are well-documented risk factors: the death or serious illness of someone close to you, a divorce, a traumatic event like a car accident or assault, or even a major positive change like having a baby. A history of childhood physical or sexual abuse also raises the risk substantially, sometimes causing panic attacks to surface years or decades later.
Chronic stress keeps your body’s fight-or-flight system running at a low hum, which means it takes less provocation to push it into a full panic response. Many people describe their first attack as coming “out of nowhere,” but when they look back, they can identify weeks or months of mounting pressure beforehand. The attack isn’t really random. It’s the point at which the nervous system’s capacity to absorb stress runs out.
Caffeine, Nicotine, and Other Substances
Caffeine is one of the most overlooked panic triggers. A review involving over 235 participants found that more than 50% experienced a panic attack after consuming caffeine, with doses above 400 mg (roughly four cups of brewed coffee). Nearly all of them had a history of prior panic attacks, and none of the participants given a placebo panicked. If you’re prone to panic, even a moderate coffee habit can keep your nervous system closer to its tipping point.
Other substances that can provoke panic attacks include cannabis (especially high-THC strains), cocaine, amphetamines, and excessive alcohol. Withdrawal from alcohol or benzodiazepines (anti-anxiety medications) is another well-known trigger, because the brain rebounds into a hyper-alert state once the calming substance is removed.
Medical Conditions That Mimic Panic
Several health conditions produce symptoms nearly identical to a panic attack, which makes them important to rule out. The most common include:
- Hyperthyroidism. An overactive thyroid floods your body with hormones that speed up your heart, cause trembling, and create a feeling of being “wired.” These symptoms overlap almost perfectly with panic.
- Heart conditions. Arrhythmias and other cardiac problems can cause sudden chest pain, pounding heartbeats, and shortness of breath.
- Respiratory disorders. Asthma and COPD can trigger the sensation of suffocating, which sets off the same fear cascade as a panic attack.
- Rare adrenal tumors. Certain tumors produce bursts of fight-or-flight hormones, causing episodes that are virtually indistinguishable from panic attacks.
- Diabetes. Low blood sugar causes shakiness, sweating, a racing heart, and confusion, all of which can feel like panic.
If your panic attacks started suddenly, happen without obvious emotional triggers, or are accompanied by symptoms like unexplained weight loss or an irregular heartbeat, a medical workup is worth pursuing before assuming the cause is purely psychological.
Medications That Can Trigger Panic
A surprising number of prescription and over-the-counter drugs list anxiety or panic among their side effects. The most common culprits fall into a few categories:
- ADHD stimulants. These medications rev up the brain and can cause restlessness, mood changes, and anxiety, particularly at higher doses.
- Corticosteroids. Drugs like prednisone and dexamethasone, used for conditions ranging from asthma to arthritis, can cause irritability and anxiety in some people.
- Asthma inhalers. Albuterol commonly causes trembling and a racing heart, both of which can feel like the start of a panic attack. Salmeterol lists nervousness, sweating, and anxiety as possible side effects.
- Thyroid replacement medication. If the dose is slightly too high, thyroid pills can push your system into a state that mimics hyperthyroidism, with shakiness, a fast heartbeat, and anxiety.
- Seizure medications. Phenytoin, used for seizures and sometimes irregular heartbeats, has been linked to panic attacks and agitation.
- Caffeine-containing pain relievers. Some headache and migraine medications contain enough caffeine to trigger anxiety in sensitive individuals.
If your panic attacks started or worsened after beginning a new medication, that timing is worth flagging with your prescriber. A dose adjustment or switch to an alternative can sometimes resolve the problem entirely.
Carbon Dioxide Sensitivity and Breathing Patterns
Some people with panic disorder have an unusually sensitive internal alarm for carbon dioxide levels. Research published in the American Journal of Psychiatry found that panic patients were significantly more reactive to inhaled carbon dioxide than healthy controls, even when they weren’t currently anxious. Their bodies interpret normal fluctuations in CO2 as a sign of suffocation, which triggers an emergency breathing response and the cascade of fear that follows.
This helps explain why hyperventilation is both a symptom and a cause of panic attacks. Rapid, shallow breathing throws off the balance of oxygen and carbon dioxide in your blood, which your brain reads as a danger signal. The more you overbreathe, the worse the dizziness and tingling become, which feeds more fear, which drives more overbreathing. Learning to slow your exhale and breathe from your diaphragm can interrupt this cycle before it escalates.
Your Gut May Play a Role
A growing body of research points to the gut as an underappreciated factor in panic and anxiety. Your gut and brain communicate constantly through the vagus nerve, the immune system, and hormones produced along the digestive tract. When the balance of gut bacteria shifts in unfavorable ways, those communication channels can amplify anxiety.
Specifically, people with anxiety disorders tend to have lower levels of beneficial bacteria (particularly Lactobacillus and Bifidobacterium species) that produce GABA and serotonin, two of the brain chemicals most involved in keeping you calm. At the same time, they tend to have elevated levels of pro-inflammatory bacteria that promote bodywide and brain inflammation. A 2025 Mendelian randomization study provided evidence that this gut imbalance is a contributing cause of anxiety, not just a side effect of it. This doesn’t mean a probiotic will cure panic attacks, but it does suggest that chronic digestive issues, a poor diet, or recent antibiotic use could be nudging your nervous system in the wrong direction.
Why Panic Attacks Seem to Come From Nowhere
One of the most distressing things about panic attacks is that they often strike without warning, sometimes even during sleep. This doesn’t mean there’s no cause. It typically means the triggers are internal rather than external: a slight shift in heart rate, a moment of shallow breathing, a digestive sensation, or a fleeting thought your conscious mind didn’t register. Your brain’s threat system processes these signals faster than your conscious awareness can keep up.
Over time, the fear of having another attack becomes its own trigger. You start scanning your body for warning signs, and that hypervigilance makes you notice every heartbeat skip, every moment of lightheadedness, every flutter of stomach discomfort. Each of those sensations gets flagged as dangerous, which edges you closer to panic. This self-reinforcing loop is the reason panic disorder develops in some people after just one or two initial attacks, and it’s also the reason treatment focused on breaking the cycle of fear (particularly cognitive behavioral therapy) is highly effective.