Is it true that psychology does not help crazy people?

No: You are wise to use the word 'help', less so for 'crazy'. But I think I know what you mean. Psychology is very helpful. Depending on the exact Dx medication may also be needed, but psychology is a big help in all cases. It's where changes are learned and understanding is gained. Best wishes!

Yes, it is true: Though descriptive, "crazy" is not a clinical useful term. It also has a wide variety of meanings to different people. Finally, it is a term that reinforces the stigma of mental health issues. That said, the field of psychology has been pivotal in helping people with all sorts of emotional difficulties feel better. So, yes.

Yes : First one must define "crazy." If you mean someone dealing with psychosis, meaning they have auditory and visual hallucinations, then yes therapy and medication can significantly help. However for disorders such as schizophrenia there is no cure just lifetime management of symptoms.

What is "crazy"?: There is no clinical definition for "crazy," so this is very difficult to answer, but I would say that in general, no, psychology and scientifically-based treatment have been shown to be effective with all diagnosable mental health disorders. Sometimes this has to be in conjunction with medication, but there are therapeutic techniques that support medical interventions for all DSM-V diagnoses.

No: What else could help a person with mental illness than psychology? I believe you mean psychotherapy and psychotherapy is known to help people win even the most severe psychiatric illnesses