What are the causes of random panic attacks?

MOST PROBABLY...: Assuming no physical basis for them, there is probably a common underlying cause connecting them. One finds out about that sort of thing in psychotherapy - and when you find out, you can change/stop them. Meds help initially, but seeing the source is key to fixing things.

Risks ; triggers.: Some things which can ^ risk for panic attacks include: previous abuse/ trauma as well as genetic predisposition. Traumatic brain injury, hyperthyroidism, hypoglycemia, mitral valve prolapse, recurrent hyperventilation, extreme physical activity, drug abuse ; use of stimulants may ^ risk. Acute stressors or chronic stress, illness, claustrophobia ; major life changes can also play a part.