If they use becks cognitive therapy a therapist will help the patient to identify negative thoughts in relation to themselves, the world and the future, using becks negative triad.
The patient and therapist will then work together to challenge these irrational thoughts, by discussing evidence for and against them.
The patient will be encouraged to test the validity of their negative thoughts. The therapist may set their patient homework to challenge and test their negative thoughts.
The ideas is that the patient identifies their own irrational beliefs and then proves them wrong.