The exact cause of panic disorder isn't clear. It is thought that it may be caused by an imbalance of chemicals in the brain (neurotransmitters). It also may be passed down through families (genetic).

You can have a panic attack without having panic disorder. Panic attacks may be triggered by:

• Drinking large amounts of alcohol or abruptly stopping the use of alcohol.
• Drinking large amounts of caffeine.
• Chain-smoking. It greatly increases the amount of nicotine in the blood.
• Taking certain medicines (such as those used to treat asthma and heart conditions) or abruptly stopping certain medicines (such as those used to treat anxiety or sleep problems).
• Using illegal drugs, such as cocaine or marijuana.
• Having high levels of stress for a long time.
• Having recently had a baby.
• Having recently had surgery or been under general anesthesia.

Panic attacks also can be caused by or linked with other medical conditions, including:

• Thyroid problems, such as an overactive thyroid (hyperthyroidism).
• Heart problems, such as mitral valve prolapse.
• Seizure disorders, such as epilepsy.
• Asthma.
• Respiratory problems, such as COPD.
• Stopping the use of a prescription medicine, such as a heart medicine.
• Depression.
• Anxiety disorders such as post-traumatic stress disorder or obsessive-compulsive disorder.