Behind the numbers: Why we need to look closer at mental disorders in type 1 diabetes

This is burdensome for anyone. What is less recognised, and even less understood, is the psychological burden that comes with T1D.

At the Institute of Psychiatry, Psychology & Neuroscience (IoPPN), in partnership with Southern Health NHS Foundation Trust, we wanted to understand how many people with T1D experience mental health problems, which ones, and their severity.

We already know T1D is linked with mental health problems

People with T1D are at higher risk of experiencing mental health problems. This has been shown repeatedly. Depression, anxiety, eating disorders, and even psychosis occur more frequently in this group than in the general population.

But this isn’t just about feeling low or overwhelmed. These are clinically distressing mental disorders. And although the risk is higher, up to half of mental disorders are never diagnosed in routine care.

That made us question “If we don’t have a clear picture of what people are dealing with, how can we offer the right support?”

The challenge of measuring what’s hidden

The difficulty lies partly in how we measure mental disorders. Most research in this area relies on short questionnaires or screens for just one condition, often depression. These tools are quick and easy, but they can miss complexity.

Less common, more severe disorders like substance use or schizophrenia spectrum disorders often fly under the radar. Even when people do screen positive, it's not always clear if they meet the threshold for a diagnosis.

Structured diagnostic interviews are the gold standard, but they are time-consuming and expensive. So, they rarely get used at scale.

Our two-phase approach: wide lens, clear focus

What we did was a feasibility study using a two-phase survey. In phase one, we asked adults with T1D to complete a broad screening survey covering a wide range of mental health problems. In phase two, we invited those who responded to take part in a structured clinical interview using the SCID-5 which is a gold-standard for diagnosing mental disorders.

We recruited from four general practices in southeast England. Of 146 eligible participants, just over half (52 per cent) completed the first survey, and about 45 per cent of those took part in the diagnostic interview.

And the results were striking. Even in this relatively small and biomedically healthier group, 81 per cent of people who completed the interview met criteria for at least one mental disorder. More than half had two or more.

These were NOT just mood disorders. Alongside depression and anxiety, people with T1D met the diagnostic criteria for eating disorders, PTSD, and substance-related disorders.

This means that in routine diabetes care, we are missing the mental disorders that people with T1D experience.

What we learnt and what needs to change

This study tells us a few important things. First, it is feasible and acceptable to carry out a wide-ranging mental health assessment in people with T1D. People were willing to take part and share their experiences.

But there are also lessons for future research. Non-responders to our survey had worse glycaemic control and more recorded mental disorders by their GPs than those who participated. That suggests we may still be underestimating the true scale of the problem.

The screening survey was also long, sometimes overwhelming, and too personal (particularly sexual health). The diagnostic interviews took up to two hours, which was a barrier for those with work or caring responsibilities.

If we want to do this work at scale, we need to be pragmatic. That might mean shorter surveys, streamlined interviews (perhaps the Mini-International Neuropsychiatric Interview (M.I.N.I)), and including mental disorders already recorded in medical notes.

What this means for care

For clinicians, the takeaway is clear. Mental disorders are common in adults with T1D and often go unrecognised. Routine care needs to move beyond screening for depression alone. It should include a broader assessment, and more importantly, provide access to psychological support that matches the complexity of what people are facing.

For researchers, this is a call to widen the lens. Mental health problems in long-term conditions are not simple, and they’re not isolated cases. We need to stop thinking in terms of single disorders and start thinking about comorbidity, severity, and impact.

Looking forward

It’s not just about what we measure, it’s also about what we miss.

We hope this work helps build a better foundation for research and care. One that sees the full person, not just the numbers on a glucose monitor.