"the places that scare you" is an audiobook by a buddhist nun called pema chodron. i dl'ed it for free from pbay
it completely changed the way i view negative emotions and taught me ways to work through how i react to them. i listen to it every time i get stuck in a rut in my life and it always brings me out of it.
its philosophy is that all our thoughts and emotions arise from a universal energy which we label as 'good' or 'bad', but in its raw form it is just energy arising. by attaching a judgement onto an emotion, it leads to us wallowing in those feelings going over and over it in our head. by realising that it is the act of running away from that feeling and the aversion to it is what causes 90% of the suffering we endure. you start to realise that you can be freed from those patterns of behaviour by learning to sit with and abide with difficult feelings/thoughts/emotions that come up. a good way to think of approaching that is picturing your despair or guilt or shame, as a baby which you are cradling in your arms with love and kindness. depression has so much to teach us, it's soo deep, there are so many facets to human suffering, its liberating to explore the root causes of it with a childlike curiosity.
i'm pretty bad at describing those concepts, but i think if your gf listened to pema's insights, it would surely help her in a fundamental way. don't be put off by this wisdom coming from a buddhist teacher, it is applicable to all humans from all walks of life.
CBT is western psychologies equivalent to mindfulness. mindfulness is the practice of staying grounded in the reality of each moment, through focusing the mind.
its very useful for her to come to terms with her thoughts and work through them in a positive way. i often find long walks in parks to give me time to organise my thoughts and give some insight into my worries, same goes for running in the evening and going swimming at the local pool.