Cognitive Behavioral Therapy.
CBT sounds complicated but the central idea is very simple: any problem we have can be though of as a vicious circle of negative thoughts, (cognitions) and feelings that result in unhelpful actions, (behaviours), that reinforce the negative thoughts and feelings. And so on...and on...and on.
In other words the way you typically react to a situation makes you deal with it even more badly the next time you meet something similar.
By working with the therapist you recognise where and how these cycles are happening and learning how to disrupt them. CBT can be effective for a wide range of problems but it seems to work particularly well with issues like panic attacks, Obsessive Compulsive Disorder, low self esteem, anger, anxiety and depression.
Both CBT and the Existential approach involve work to try and uncover the 'default settings' we fall back on in life and in that way the two approaches can often fit together well.