Historian Page Smith, formerly of UC Santa Cruz, spoke in his volume on the Reconstruction, Trial by Fire, about "social psychosis." He defined this as an historical perspective that an entire society holds that from a later historical perspective was seen to be socio-cultural madness. He applied this to the South's belief that slavery was justifiable and tenable. He suggested this social psychosis was amplified by the simultaneously held that humanistic philosophy and Christian religious doctrine were true. If I understand your question correctly (ans I'm not certain I do), Smith's is an example of the application of interdisciplinary insanity theory. The "issues" of insanity and history, if this is what "issues" you mean, are comparable, thus suited for interdisciplinary study, because both focus on peoples' behavior, collectively and individually.
A true picture of madness could only be contrived through interdisciplinary studies. A clinical portrayal or research and statistics would be a very empty definition. Someone researching madness would need to incorporate many more perspectives on the issue, including cultural, historical, literary, and social views on the subject. The above post mentioned To Kill a Mockingbird and Jane Eyre as great examples of a literary portrayal of madness, and also society's response to it, which was to conceal the issue by hiding away the family member, but The Yellow Wallpaper also gives readers another perspective from a female perspective, making a strong case for how women's mental health was often overlooked or neglected.
It is interesting to think about the historical views of insanity or madness from how it is discussed by different generations. My grandmother need anti-depressant pills but she would never discuss that with friends or family. That discussion was held only with her doctor. This led to some very scary incidents for my mother while she was young. She came home from school once to find her mother passed out on the stairs but she didn't know why. My mother had to guess about her mother, and walk on egg shells, because nothing was ever discussed. My mom ended up reading tons of psychology books to help her to understand her mother's mental illnesses. It wasn't until my generation that the subject of mental illnesses could be discussed more openly in society and in family units. Literature can also give insight to how other generations responded to mental illnesses.To Kill a MockingbirdandJane Eyreare both books about families hiding away other family members to keep them safe or to keep them a secret from society. As with all human differences and prejudices, it seems as if scientific reforms and studies need to be accepted as household discussion topics through social acceptance before they are ever modified.
As insanity is not only a psychological subject, but a social and scientific one as well. This makes an interdisciplinary approach to insanity sensible - and/or makes a comparison between interdisciplinary studies and the study of insanity sensible.
As the post above states, Foucault suggested that insanity is a culturally crafted definition, not unlike other social norms, taboos, and categories based largely on value-based ideas.
If madness is not only a state of mind but a social status, we have a quite complex issue on our hands...
One famous example of an interdisciplinary study of "madness" was Michel Foucault's Madness and Civilization, which you asked about in the Q and A section. Essentially, Foucault showed that mental illness had a history, that it meant different things at different times, and he argued that defining "madness" was a powerful way of enforcing the mores of the day by proscribing those who exhibited abnormal behavior. The emerging science of psychology, Foucault argued, involved a process of exercising power over the minds of the "mad" by not simply curing or "brainwashing" them, but by causing them to understand their own madness and submit to punishment, cure, confinement, or simply reforming their behavior.
What insanity is has varied considerably in different times and cultures, a very interesting notion, don't you think? And not surprisingly, how insanity is treated has differed dramatically, depending on time and place. By "treated," I mean "regarded as," as well as how symptoms have been addressed. This has not necessarily been because medical advances have changed things, as because of culture and attitude. Given that, some knowledge of anthropology, sociology, and history, at the very least, can be very useful in placing the concept of insanity in context.
Interdisciplinary studies can be used to study mental illness. For example, the medical field will look for a different cause or explanation than the psychological field. Since the human mind is so complex, looking at symptoms from different perspectives can help to identify and possibly treat the illness.
For example, it is an oversimplification to suggest that there are biomedical, behavioral, and clinical fields.
There are many disciplines within each of these areas and significant overlap in and between these three major groupings. (ncbi)
A broader look at human nature will result in more complete and helpful treatment options. Every aspect of the health system needs to work together to diagnose and treat mental illness.