A real life example. The best way to understand schemas and core beliefs is through example. Let's say "Jack" was recently dumped by his girlfriend. Jack's girlfriend explained that she was breaking up with him because is moving and doesn't want a long-distance relationship. Although she says she cares about him, she thinks it's best that they end the relationship.
Jacks feels intensely heartbroken about the breakup (and these feelings are valid and understandable). Jack tries to understand more about why his girlfriend dumped him so his brain begins to create a story with additional information about why the breakup happened. His thoughts tell him that his girlfriend never actually cared about him and that she secretly hated him all along. He thinks about all his perceived flaws, that he isn't attractive enough, clever enough, or successful enough. He also thinks to himself that he will never meet anyone again and will remain single for the remainder of his life.
CBT In Action
Can you see the cognitive distortions in the above example? Jack is catastrophizing, jumping to conclusions, thinking in certainties, overgeneralizing, and personalizing. In CBT, Jack will learn how to become more aware of these cognitive distortions and challenge them to create more accurate and emotionally neutral thoughts. Although the concept of restructuring thought patterns is relatively simple, it's far from easy.
If Jack has a difficult time buying into the fact that his thoughts are extreme judgements that are likely inaccurate and ineffective, his CBT therapist will explore the core beliefs at the root of his thoughts. Through therapy, Jack will likely learn that he has a negative view of himself which is acting as jet fuel to his negative thought patterns. His therapist will help him explore this deeper and to correct not only his faulty thoughts but his faulty core beliefs as well.
If Jack actively participates in CBT, he will learn the skills to correct his thinking. CBT is very effective for many folks, therefore it is very likely that therapy will be successful in reducing the intensity of his distress and help him heal from the breakup. He will also likely be more resilient to stress in the future.