Receiving a mental illness diagnosis can be profoundly validating for many people. A diagnostic label often brings relief, language, treatment, and support. A diagnosis can transform years of feeling lost into more understanding and access to support, community, and enhanced relevant language.
But this profound usefulness of current diagnostic labels does not necessarily equal biological or neurological underlying truth. Nor does the experienced usefulness of a psychiatric classification system indicate that enhancements cannot be made.
Researchers and clinicians increasingly recognise that the categorical conditions identified in current psychiatric manuals may be overly rigid and simplistic models of how human minds work. Human psychology rarely lets itself be boxed into neat, isolated conditions with crisp boundaries. Instead, mental health challenges often overlap, interact, and shift across development, and are susceptible to context and environment.
Many people diagnosed with one condition eventually collect several more. Attention-deficit/hyperactivity disorder (ADHD) and anxiety… Autism and depression… Complex posttraumatic stress disorder (cPTSD) and phobia…
The boundaries between diagnoses, in real life, are often far more blurred than our manuals suggest. One option is that there is simply high comorbidity between many conditions (and also between different expressions of neurodivergence). But perhaps the issue is not simply comorbidity.
Perhaps our current categories themselves are incomplete elements of maps of human experience.
The Simplistic Box Model of Mental Health
Modern psychiatric models, such as the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD) were developed to improve consistency in diagnosis and communication. Historically, this has represented important progress. Diagnostic categories have given clinicians, researchers, and clients shared language, guided research, informed treatment decisions, and supported many people to access more targeted support.
But categorical models, while succeeding in the above, also assume that mental illnesses exist as relatively distinct entities with identifiable boundaries and core characteristics that are consistent across individuals.
In practice, such boundaries are often far less clear than the manuals would make one think. Two people with the same diagnosis may present with behaviours and cognitions profoundly different from one another. One person diagnosed with ADHD may struggle primarily with attention regulation, while another experiences primarily emotional sensitivity, chronic overwhelm, and sensory difficulties. Likewise, someone diagnosed with autism may also meet criteria for anxiety, depression, eating disorders, or trauma-related conditions.
Comorbidity is so common that it raises an essential question: Are we observing multiple separate conditions, or are our categories carving underlying dimensions of human experience into artificial, sub-optimally fitting divisions?
Difficulties with attention, emotion, reward processing, cognitive control, and social cognition often exist on a continuum rather than appearing as simply present or absent. Increasingly, dimensional and transdiagnostic models of mental health, including efforts such as the Hierarchical Taxonomy of Psychopathology (HiTOP) and predictive processing frameworks, attempt to capture this biological complexity more accurately.
Rather than asking whether someone fits neatly into a category or box, such approaches ask how different dimensions at different levels interact to shape experience and mental health and illness.
When Categories Become Too Rigid
Diagnostic categories undoubtedly remain as clinically useful shorthand. But when such categories become too rigid, important aspects of the human experience can be lost.
Currently, this contributes to missed diagnoses, misdiagnosis, stigma, and people feeling fundamentally “broken.” Furthermore, our current approach can also overlook strengths and obscure contextual and environmental influences.
This becomes particularly relevant for women, gender-divergent individuals, and a whole host of minority groups whose presentations often differ from historically dominant diagnostic prototypes. As a result, many people spend years trying to understand themselves through categories that at best partially capture their lived experience.
Sometimes the issue is not that people fail to fit the box. Sometimes the box fails to capture the complexity of people.
Brené Brown has written that “with an adventurous heart and the right maps, we can travel anywhere and never fear losing ourselves.” Her work on belonging and emotional life emphasises the importance of understanding the terrain of human experience rather than forcing ourselves to simply “fit in.”
Diagnostics may require a similar shift. Our current systems often function like rigid borders defining siloed boxes: you either fit the box or you do not. But human minds rarely organise themselves into such clean divisions. Perhaps what we need are “simply” better maps.
Mapping Mental Health
Importantly, a map-based approach asks different questions than a categorical, siloed approach.
Not: “What disorder does this person have?”
But:
How does this person process sensory, emotional, or social information?
What environments overwhelm or energise them?
How do they experience uncertainty, reward, belonging, or stress?
What patterns emerge across development and context?
Which traits create challenges, and which create strengths?
Maps prioritise dimensions and connections, relationships, and movement rather than rigid borders. A diagnosis may identify part of the terrain. But it rarely captures the full landscape of a person’s mind.
Mental illness may be less like separate diseases and more like interacting dimensions shaped by biology, development, social interactions, and environment. Two people may share a diagnosis while possessing entirely different cognitive profiles, support needs, and strengths. Likewise, one person may meet criteria for several diagnoses simultaneously because the underlying dimensions overlap.
A map-based approach allows us to hold this complexity more honestly. Importantly, maps do not deny suffering. Nor do they romanticise it. Many forms of psychological distress are deeply impairing and deserve compassionate, evidence-based support.
But a more dimensional understanding may also help us move beyond purely deficit-focused models toward approaches that recognise strengths, adaptation, and environmental fit alongside difficulty.
Why This Matters
How we classify mental health and illness shapes how people understand themselves.
Rigid categories can unintentionally encourage people to see themselves as disordered, defective, or fundamentally separate from others. Maps, by contrast, invite a more nuanced understanding of variation, context, and individuality.
This shift has practical implications. It may support more individualised interventions, reduce shame, improve recognition of neurodivergent presentations, and help prevent burnout caused by a chronic mismatch between people and their environments.
The boundaries between diagnoses may reflect the limits of our classification systems more than the natural boundaries of the mind itself.
Categories may still help us name suffering. But maps may help us understand people and biology more closely.