Anxiety and panic attacks arise from a combination of brain chemistry, genetics, life experiences, and physical health factors. There is rarely a single cause. For most people, these conditions develop when several risk factors overlap, creating a nervous system that responds too strongly to perceived threats. Globally, anxiety disorders affect an estimated 359 million people, making them the most common mental health condition in the world.
What Happens in Your Brain During Panic
The core of both anxiety and panic attacks traces back to your brain’s threat-detection system. A small, almond-shaped structure deep in the brain acts as your fear alarm. When it fires, it triggers a cascade of physical responses: your heart races, your breathing speeds up, your muscles tense, and stress hormones flood your bloodstream. In a genuine emergency, this keeps you alive. In a panic attack, the alarm fires without a real threat.
Research shows that electrically or chemically stimulating this fear center in the brain produces a set of symptoms nearly identical to a panic attack. People with panic disorder appear to have heightened reactivity in this region, along with structural differences similar to those seen in post-traumatic stress disorder. When the brain’s natural braking system fails to keep this area in check, sudden spikes in anxiety can occur without warning.
That braking system relies heavily on a chemical messenger called GABA, the brain’s primary calming signal. Roughly one-third of all neurons in the central nervous system use GABA to communicate. It works by making neurons less likely to fire, keeping excitation and inhibition in balance. When GABA signaling is weak or disrupted in the fear center, the result can be runaway anxiety or sudden panic. This is why medications that boost GABA activity, like benzodiazepines, can quickly reduce acute anxiety symptoms.
Genetics and Family History
If a close relative has panic disorder, your risk is meaningfully higher. Twin studies estimate that genetics account for 30% to 40% of the risk for panic disorder. Identical twins, who share all their DNA, have a significantly higher rate of both developing the condition compared to fraternal twins. This tells researchers that a substantial portion of vulnerability is inherited, though it also means 60% to 70% of the risk comes from non-genetic factors like environment and life experience.
No single gene causes panic disorder. Instead, many genes each contribute a small amount of risk, likely by influencing how your brain produces and responds to chemical messengers involved in fear and stress regulation. Having a genetic predisposition doesn’t guarantee you’ll develop an anxiety disorder, but it can lower the threshold for other triggers to push you over the edge.
Childhood Adversity and Trauma
What happens to you early in life shapes how your brain handles stress for decades. Adverse childhood experiences, including abuse, neglect, household instability, and loss of a caregiver, have a moderate but consistent effect on adult anxiety levels. One recent study found that more than half of the link between childhood adversity and adult anxiety operates through changes in how people think about their own thoughts. Specifically, early trauma tends to produce persistent negative beliefs about worry itself (“my worrying is dangerous,” “I can’t control my thoughts”), which creates a feedback loop that amplifies anxiety over time.
Traumatic experiences at any age can also sensitize the brain’s stress response system. The hormonal stress axis, which controls the release of cortisol and other stress hormones, can become dysregulated. In panic disorder, this disruption tends to develop after the condition has been present for a while, particularly once a person begins living in fear of the next attack. That anticipatory dread becomes its own source of chronic stress.
The False Suffocation Alarm
One of the more compelling theories about panic attacks specifically involves carbon dioxide sensitivity. The idea, known as the false suffocation alarm theory, proposes that people with panic disorder have an overly sensitive internal monitor for suffocation cues. When blood CO2 levels rise even slightly (something that happens naturally during exercise, in stuffy rooms, or during certain breathing patterns), the brain misinterprets this as a sign of suffocation and triggers a full-blown panic response.
This theory helps explain several puzzling features of panic attacks: why they sometimes strike during sleep, why they can happen during relaxation when you’d expect to feel calm, and why hyperventilation (which rapidly lowers CO2) is so common during episodes. Elevated lactate levels in the brain, which shift blood chemistry in a similar direction, may also trigger panic through the same chemical-sensing pathways in the fear center.
Substances That Trigger or Worsen Panic
Caffeine is one of the most widely studied panic triggers. It blocks receptors that normally have a calming effect on the brain, and research confirms that it targets mechanisms directly related to the development of panic symptoms. For people already prone to panic disorder, even moderate caffeine intake can provoke or intensify attacks. If you’re experiencing frequent anxiety, reducing coffee, energy drinks, and tea is one of the simplest changes to test.
Alcohol creates a different problem. It initially boosts GABA activity, which is why a drink can feel calming. But as your body processes alcohol, GABA levels drop below baseline, often producing rebound anxiety hours later or the next morning. Stimulant drugs, including nicotine in high doses, amphetamines, and cocaine, directly activate the body’s fight-or-flight response and can trigger panic attacks even in people with no history of anxiety. Withdrawal from alcohol, benzodiazepines, or other sedatives is another well-established trigger, as the brain suddenly loses the chemical support it had adapted to.
Medical Conditions That Mimic Panic
Several physical health conditions produce symptoms that are virtually indistinguishable from a panic attack, and they’re worth ruling out. Hyperthyroidism is one of the most commonly missed. An overactive thyroid causes palpitations, trembling, sweating, rapid breathing, restlessness, difficulty concentrating, and disrupted sleep. These overlap so heavily with anxiety disorders that misdiagnosis is common, sometimes delaying proper treatment for months or years.
Heart rhythm abnormalities can also feel exactly like panic: sudden racing heartbeat, chest tightness, dizziness, and a sense of dread. Other conditions that can produce panic-like symptoms include low blood sugar, inner ear disorders (which cause dizziness and disorientation), asthma, and adrenal gland tumors that release bursts of adrenaline. If your panic attacks came on suddenly without an obvious psychological trigger, or if they’re accompanied by other unexplained physical symptoms, a basic medical workup including thyroid function and heart rhythm testing can clarify what’s happening.
How These Symptoms Feel
A panic attack is an abrupt surge of intense fear that peaks within minutes. To meet clinical criteria, at least four of the following symptoms occur together: racing or pounding heart, sweating, trembling, shortness of breath, a choking sensation, chest pain, nausea, dizziness, feelings of unreality or detachment from yourself, fear of losing control, fear of dying, numbness or tingling, and chills or heat sensations.
The experience is often terrifying precisely because the physical symptoms feel so real and intense that many people believe they’re having a heart attack or dying the first time it happens. Generalized anxiety, by contrast, tends to build more gradually and persist as a steady background of worry, muscle tension, fatigue, and difficulty sleeping. Both conditions can exist independently or feed into each other. Someone with generalized anxiety may develop panic attacks over time, and repeated panic attacks almost always generate ongoing anxiety about when the next one will strike.
Why It Rarely Comes Down to One Cause
Most people who develop anxiety or panic disorder have multiple contributing factors working together. You might inherit a brain chemistry that’s slightly more reactive to stress, experience childhood adversity that further sensitizes your stress response, drink several cups of coffee a day, and then go through a major life change like a job loss or breakup. Any one of those factors alone might not be enough. Together, they can push a nervous system past its tipping point.
Understanding your specific mix of causes matters because it points toward what’s most likely to help. Someone whose panic is driven primarily by CO2 sensitivity may benefit most from breathing retraining. Someone whose anxiety is rooted in childhood trauma may need a therapy approach that addresses those deep patterns. And someone whose “panic attacks” are actually driven by an overactive thyroid needs medical treatment, not anxiety management. The causes are multiple, but they’re identifiable, and that makes them treatable.