When It’s Not All in Your Mind: How Chronic Health Conditions Affect Mental Health

Many people living with a chronic health condition have been told at some point that their symptoms are “just anxiety” or “just stress”. While stress and anxiety are very real, this framing can miss something important. The relationship between the body and the mind runs in both directions, and for many chronic health conditions, changes in mood, energy and thinking may be part of the condition itself rather than a separate psychological problem.

The body and brain are in constant conversation

The gut, the brain and the immune system are in constant two-way communication, which researchers often refer to as the gut-brain-immune axis. Signals travel between them through the vagus nerve (a long nerve connecting the brain and the gut), through the immune system and through substances produced by the bacteria in our gut. This means what is happening in the body can influence how we feel, think and respond, and stress in turn can influence how the body functions.

A helpful example is how most people feel when they have the flu. Along with the physical symptoms, people commonly feel foggy, flat and withdrawn, and want nothing more than to stay in bed. This is partly due to the immune system releasing chemical messengers called cytokines, which signal the brain to slow down and rest. This response is sometimes called “sickness behaviour”, and it is the body’s way of encouraging recovery.

What this can look like in chronic illness

In conditions involving ongoing inflammation, such as coeliac disease and other autoimmune conditions, a similar process may be happening on a longer-term basis. Inflammation can contribute to fatigue, brain fog, low mood, poor sleep and anxiety. In some conditions, damage to the gut can also affect how well nutrients such as iron, B12, folate and vitamin D are absorbed, all of which play a role in energy, mood and concentration.

Interestingly, research has found that in some people with coeliac disease, anxiety and depression appear before the diagnosis is made. This suggests that the mental health impact is not only about adjusting to a new lifestyle, there may also be a biological contribution that is present well before anyone knows what is going on.

The connection also works in the other direction. Stress and anxiety can change how the gut moves, how sensitive it is and how it responds, which can make physical symptoms feel worse. This can create a cycle where symptoms increase worry, and worry increases symptoms.

Why this matters

Recognising the biological side of mental health is not about saying that nothing can be done. It is about making sure people are not blamed for experiences that are partly driven by their body. When anxiety is linked to inflammation, an adrenaline response or a lack of sleep, being told to simply think differently can feel invalidating and may leave people feeling more misunderstood than before.

Understanding the full picture means that both sides can be supported. This may include making sure the physical condition is well managed, having nutrient levels checked by a GP, and finding a psychologist who understands chronic illness and can work with both the physical and emotional experience. It may also include support with sleep, pacing and gentle movement, which can all help to calm the stress response.

A whole person approach

The mind and body are not separate systems, and chronic health conditions are a clear example of how closely they are connected. If you are living with a chronic condition and finding that your mood, energy or thinking has changed, it is not a sign of weakness or of doing something wrong. It may be your body asking for support, and it deserves to be taken seriously.