Yes, there has been research conducted on mutual understanding between mentally ill patients. One example of this is a study conducted by the University of Southern California which found that creating a “safe space” for mentally ill patients to talk and share their experiences can help foster mutual understanding and respect. The study concluded that providing a safe space for open communication can help reduce stigma and create a more accepting environment for everyone. Other research on mutual understanding between mentally ill patients has focused on the importance of creating a non-judgmental atmosphere and providing opportunities for collaboration and understanding between mental health professionals and those affected by mental illness.

Again, there is some research that suggests that people with mental disorders can have a better understanding and relationships with other people with mental disorders than with those without mental disorders. For example, a recent study conducted by the University of Arizona found that people with mental illnesses had greater empathy and understanding for those with similar mental health conditions. This study also found that people with mental illness tend to have better relationships with other people with mental illness than those without mental illness. Additionally, research published in the International Journal of Mental Health Nursing found that people with mental illness can have meaningful relationships with other people with mental illness, which can help reduce their sense of isolation and provide greater support. This research also suggests that people with mental illness can provide important insight into the experiences and challenges of living with a mental illness.

Mentally ill is not a very helpful term here. Mental illness is a whole variety of conditions ranging through things as diverse as post-traumatic stress, obsessive-compulsive disorder, complicated grief, schizophrenia, affective psychosis, dysmorphophobia : all so different at so many levels.

Maybe focus in on a particular area.

There is a lot of anecdotal evidence of this and some studies that were mentioned by others who answered your question. A key expression of putting this into practice is the self-help movement and funded consumer/survivor groups. In the 1990s I worked on this in Ontario, Canada. The government decided to fund 42 of these and all were governed and staffed by people with lived experience. Some research results were reported: Trainor, J., Shepherd, M., Boydell, K., and Leff, A., and Crawford, E. “Beyond the Service Paradigm: The Impact and Implications of Consumer/Survivor Initiatives.” Psychiatric Rehabilitation Journal. 21 (2): Fall 1997. When working with my team on the Ontario project we asked 500 people with lived experience a simple question: Who has been most helpful to you in dealing with your mental illness? The answer "Other poeple with mental illness" was the first choice. Family and friends came second and professionals third. One way to think about this is to realize that there are many resources beyond professional services that help people. One is self-help. This is also true for families. You can find a recap of the Ontario experience in a chapter (Trainor, J,; Reville, D. "Begining to Take Control: Ontario's Consumer/Survivor Development Initiative") in Nelson, G. et al Community Psychology and Community Mental Health, Oxford University Press, 2014.

John N Trainor thank you very much! It was very helpful!

I agree with Ronan that "mentally ill" is not a helpful term. I would like to point out, though, that many people with mental health condition change diagnosis over time. Some service users comment that "my diagnosis was changed but I was the same distressed person" which may point to foundational factors such as post-traumatic mechanisms.

Also, many people have two or more diagnoses at once, including psychotic disorders, BPD, PTSD, depression and anxiety disorders. Which can explain the mutual understanding of people with lived experiences of mental distress - beyond this or that specification.

(see for example Vaidyanathan U, Patrick CJ, Iacono WG. Patterns of comorbidity among mental disorders: a person-centered approach. Compr Psychiatry. 2011;52(5):527-535)

Apart from the research literature, I would recommend looking at the grey literature written by service users / consumers / ex-patients / Mad people.

The Routledge International Handbook of Mad Studies might be a good place to start:

https://www.routledge.com/The-Routledge-International-Handbook-of-Mad-Studies/Beresford-Russo/p/book/9781138611108#

I do endorse many of the answers to this question, but have trouble understanding why it was asked in the first place. I have worked in mental health rehabilitation for many years with professionals, families, and those with lived experience. I actually believe that the capacity to understand another human is an individual quality, not an attribute of a particular mental illness. If the question is based on an assumption that those living with mental illness are somehow less capable of understanding another person with a different mental health profile, then the question is absurd. We all have different mental health profiles, just as we all have different physical health profiles. From a logical point of view I would think it more reasonable to assume that capacity to understand another is independent of mental health profile, but more likely to be related to the extent that two people share similar life experiences. That would include experiences of different mental and physical states. Does that make sense?

Geoffrey Rolland Waghorn yes, I understand your point of view. Of course, it depends on personal characteristics and life experience. but the concept of life experience also includes the disease that a person suffers from. accordingly, it seemed to me that there are studies that deal with mutual understanding between patients with same diagnoses

Tamar Ben-Barak Thank you very much for the answer!

I think it is useful to think of "lived experience" in more than one way. Following the comment by G. R. Waghorn, I agree that there is an underlying level of experience that can enhance communication between someone without a diagnosed mental health issue and someone with a diagnosis. This draws on the common elements of us as human beings. Above this level, however, we can think of 2 more. The first is elements of lived experience that come with having a diagnosis, any diagnosis, including, for example, the experience of stigma and prejudice. These elements might be called the socially determined position of someone with a mental illness. This of course varies widely in different societies. The third level might be seen as elements of lived experience that pertain to a particular diagnosis. For example, people with bipolar have experiences that are different from people with schizophrenia. People with the lived experience of paticualr diagnoses have demonstrated this by forming diagnostically specific self-help groups in areas like mood disorders and anxiety. These groups exist because of the common experiences, based on a particular diagnosis, shared by these people.

So, if we think of "lived experience" in this way we can see that it is a complex concept. In the work I mentioned in my previous note, the focus chosen by most of the 42 groups was the second level - the common experience of being a "mental patient" (their term) in our society. The groups were typically non-diagnostic and focused on inclusion and anti-stigma.