You can’t do anything about her delusions. It’s a symptom of the illness. The last thing you want to do is “confront” her delusions. It’s very likely that no matter what evidence you present, it would make no difference. That is the nature of delusions.
By definition, a delusion is a belief that is firmly held despite evidence to the contrary. Attempting to dissuade her of a delusion may do more harm than good. It may only cause her to become upset with you, create chaos in the family, or make her trust you less, and so forth.
The delusion may eventually go away or may shift into something else. That has already happened once. It used to be that she thought she was the psychopath and now she thinks it’s her sister. It may shift again but for now, avoid the discussion whenever possible. If she brings it up, change the subject. Understandably, that might increase her suspiciousness but the last thing you want to do is attempt to disprove delusional ideas. It’s a battle you can’t win.
Medication helps but it can only do so much. It’s fairly common for individuals with schizophrenia to take medication that reduces most of their symptoms but not all of them. There are often remnants. A different medication might help to reduce this particular delusion but with all the other positive aspects of her recovery, it may not be the right time for her to switch. Discuss it with your sister and her psychiatrist, should the need arise.
I would recommend reading the book I’m Not Sick, I Don’t Need Help written by Dr. Xavier Amador. It’s an excellent book about common issues families face when caring for a family member that has schizophrenia.
In the book, Dr. Amador explains that about 50% of people with schizophrenia do not believe that they are ill because of a condition called anosognosia. Anosognosia is a symptom of the illness. It involves the idea that an individual does not know that they are ill. It’s also referred to as “lack of insight.” It’s not thought to be something that a person is deliberately doing to be difficult. Rather, people with anosognosia truly do not know they are ill.
Anosognosia is also found among people with Alzheimer’s. At some point during the progression of the disease, an individual with Alzheimer’s loses the ability to recognize that they are ill.
If an individual doesn’t think they are ill, it logically follows that they would not believe that they need treatment for an illness that they don’t think they have. Thankfully, your sister continues to take medication, however, you did mention that there are times when she tries to skip it. That’s fairly common among people with schizophrenia. One has to be careful not to skip medication, especially with schizophrenia. Stopping medication can cause a relapse. It is a very common problem among people with schizophrenia.
I think that you’ll find the aforementioned book helpful for gaining a deeper understanding of schizophrenia and how families can best interact with a loved one who has the illness. It contains many great tips and ideas for family members in situations like yours. There are many other good books in addition to resources on the internet.
You mentioned that your older sister is currently not living in the family home because of your sister’s delusion about her. That’s probably a good idea for now. As mentioned previously, her delusion may shift or potentially go away but only time will tell.
The most important thing is to encourage your sister to continually take her medication and to remain in treatment. That can often be difficult to do especially if an individual does not believe that they have an illness. When it comes to schizophrenia, continuous treatment is of paramount importance. Consistent treatment is correlated with fewer episodes and hospitalizations and an overall better prognosis.
I hope this helps. Please write back if you have additional questions. Please take care.
Dr. Kristina Randle