Theorists debate many questions surrounding mental disorder, including, most importantly, what mental disorder is. (I use “mental disorder” instead of “mental illness” as many these days prefer the first term.) Contemporary theorists disagree about whether it is possible to give an account of mental disorder that avoids all mention of human interests and concerns, i.e. human values. I argue that it is impossible to avoid values when defining mental disorder and propose an account that references the concept of individual welfare. In other words, on my view, mental disorder is something that undermines a person’s ability to live well. Finally, I use this account to shed light on questions surrounding both diagnosis and treatment.

Most accounts of mental disorder wrestle with questions about values. Their question is whether it is possible to explain both what mental disorder is as well as identify particular mental disorders without making reference to things that individuals and/or society deem important. For example, some would say that mental disorders are simply mental dysfunctions whereas others think that we must call these harmful dysfunctions to make the concept coherent (with harm being an evaluative term). Those who oppose references to values worry that allowing values into our accounts will mean our categories remain vague, and that this may leave diagnosis open to bias and abuse. Those who oppose appeal to values are generally referred to as “naturalists” whereas those who insist that values are unavoidable are called “normativists.”

In the first part of my dissertation, I argue that naturalist accounts of mental disorder are untenable and propose a normative account in which the relevant value judgments are clearly defined. In contrast with accounts that appeal to social values, I appeal to a notion of individual welfare. Mental disorders, on my view, are clusters of symptoms that significantly lower an individual’s welfare. To fill out this account I need a theory of individual welfare. I appeal to a contemporary view known as “the value fulfillment theory,” which posits that an individual’s life goes well or poorly for them to the extent that they are able to pursue and realize their values, i.e. what matters most to them. So a mental disorder is something that significantly impedes a person’s ability to pursue or fulfill their values. 

After building this account of mental disorder in the first two chapters, I then turn to some practical questions and considerations, the first of which is diagnosis. I offer additional requirements for diagnosis that determine whether the impact of mental symptoms to someone's well-being is significant. Mental symptoms may often interfere with someone's ability to fulfill their values, but these symptoms only constitute a disorder if they lower well-being significantly. These requirements for significance solve the problem of threshold in psychiatry, or determining what is disorder versus non-disorder. I show how these requirements may be incorporated into current diagnostic criteria using three separate case studies. Importantly, this discussion demonstrates our current conception's inability to handle cases of grief or expected emotional distress, where the welfarist account of mental disorder can.

The debate surrounding grief is similar in the sense that it requires clinicians to ask questions about the appropriateness of a mental state or condition. We expect people to grieve at various points in their lives. We also expect that grief will cause suffering and lower the grieving individual’s welfare. Many theorists and clinicians argue that grief does not constitute a mental disorder, since it is seen as a normal part of life. This is often based on the assumption that mental disorders are mental abnormalities. My account of mental disorder offers a different perspective and can help shed light on those cases in which grief might require diagnosis and treatment. In other words, I offer a “middle view” of grief, in which it is not whether grief is natural that matters, but whether it is lowering individual welfare. Some grief will resolve on its own without significantly lowering welfare—at least not over the long term. But some grief will affect individuals significantly in the long term, and that grief should be treated.

Finally, I turn to questions and concerns about treatment. I offer that treatment is aimed at repairing an individual's relationship with their environment, and discuss how the welfarist account can inform treatment plans. I also consider some of the potential risks associated with treatment and how those risks may be either overstated, or can be easily mitigated.