Those are some references for you

This one also

This is a good one

Check this one too

You should look for the work of Barbara Milrod. She as published several papers on the use of Psychodynamic Psychotherapy for the treatment of Panica Disorder.

Her work is available here in ResearchGate, just search for her name and you can download several of those papers.

All the Best,

Guilherme

Two very effective therapies (there are also pharmacological drugs) are Cognitive behavioural Thrapy and Meta Cognitive Therapy. Go the Meta Cognitive Institute on metacognitive therapy of Dr Adrian Wells, they have been extremely successful with Anxiety Disorders and specifically with Panic disorders.

You may be artificially limiting your search by focusing on adolescents, because many of the strategies that work for adults also work for adolescents. The differences might be that incomplete frontal lobe connectivity in adolescence may make metacognition more difficult, and may make it more difficult to manage the impulse to escape a situation in which the patient fears the onset of a panic attack. If this is the case, you could overcome those developmental weaknesses by practicing more of the techniques in the therapy office or elsewhere with an adult serving as a coach.

Psychotherapy in my experience has a few components:

1) education about the overactivity of the sympathetic nervous system, or in layman's terms, the fight or flight system or even the "false alarm."

2) observation/insight that anticipation and avoidance are bigger and more frequent daily problems than the panic attacks themselves, and that both anticipation and avoidance make panic attacks worse in the long run; (In adults, sometimes this alone makes a huge difference; adolescents might not have a long enough track record to see this pattern)

3) exposure therapy plan, practice in and outside of sessions, involving experience and acceptance of the "false alarm" symptoms, not "obeying" the alarm by trying to escape; this may require practice manipulating individual symptoms such as rapid heart rate or difficulty breathing. The goal is to see the symptoms as annoying rather than alarming. If the goal is to eliminate the panic symptoms entirely, clients will be justifiably fearful that an attack might still happen at some point; my preference is that they practice being prepared for this possibility.

Again, limited metacognition in a 12 year old might make all three of these steps more difficult to understand and act on; I find it useful to use the analogy of not listening to the annoying smoke detector when it goes off but there's no real fire.

As for medication, benzodiazepenes can feed into the escape cycle and won't be used in many adolescents anyway; SSRIs, though, can make the cognitive components work better, and if you happen to have an adolescent with Panic Disorder and ADHD, the dopamine transporter blockers (Ritalin etc) may help suppress the avoidance impulse.

Disclaimer; though I've worked in a psychiatric practice, and I've even stayed in a Holiday Inn Express, I am not a physician, so take the medication information as my personal experience and opinion.

It would be helpful to know the age range you have in mind or other reason you have for feeling that treatments for adults might not be applicable or appropriate. Exposure therapy (exposure to situation and to isolated components of the panic attack itself) still seems like the basic straightforward brain-based treatment.