Chronic illness and mental health: why they are connected, and what can help

Image: Photo by Shane on Unsplash

A long-term health condition asks something of you every day, and not only in the places you would expect.

The fatigue that does not lift with rest. The appointment you find yourself bracing for. The morning when getting dressed takes more time than it used to. And underneath the practical load, a quieter weight: the worry about what comes next, the frustration at a body that no longer does what it once did, the low mood that has settled in alongside everything else.

People often experience these as two separate problems. There is the illness, and then there is the emotional toll, which can feel like a personal failing, something that ought to be manageable with enough resolve. But the body does not keep physical health and mental health in separate compartments. They move through many of the same systems, and they shape each other constantly, in both directions. Seeing how that works changes what it makes sense to do.

Because the systems are not separate. A long-term illness is a sustained demand on the body, and the body responds to sustained demand the way it always has, by switching on the stress response and keeping it running. Stress hormones stay elevated. Sleep and appetite are nudged off their usual settings. Less is left in reserve for everything else. These are the same systems that shape anxiety and low mood, which is part of why the two travel together so often. The link also runs through daily life, as pain, fatigue, and the constant work of managing a condition wear at mood directly.

This is common, not a sign of weakness. In Australia, around 1.7 million adults, roughly one in twelve, live with both a long-term physical condition and a mental health condition (Australian Bureau of Statistics, 2023). And the connection carries real weight in both directions. In diabetes, for example, co-occurring depression has been associated with poorer physical outcomes over time (Prigge et al., 2022). Low mood and anxiety can make it harder to sleep, stay active, eat well, and keep up with treatment, which then feeds back into the condition itself.

So if your mood has shifted since your diagnosis, you are not failing to cope. You are having a recognised response to a real and ongoing load. That matters because it changes what makes sense to do. The emotional side of a long-term condition is not separate from your health. It is part of it, and it responds to care.

The instinct, when the body feels like it is letting you down, is to push harder against it. Force the energy. Override the fatigue. Talk yourself out of the worry. With a long-term condition, that usually costs more than it returns, because much of what the body is doing is protective. It is conserving energy. It is staying alert. The aim is not to defeat those responses but to work with them, giving the system small, regular signals that it is safe to settle. Most of what helps falls into three moves: settling the system, working with your energy, and not carrying it alone.

The first move is to settle the system, and small, repeatable signals do more here than grand gestures. The breath is the most portable of them. Lengthening the out-breath for a few minutes tells an activated nervous system that the emergency has passed, and a 2023 meta-analysis of randomised trials found breathwork was associated with lower stress, anxiety, and depressive symptoms, though the researchers rightly called the evidence still developing (Fincham et al., 2023). Light matters just as much and is one of the best understood signals there is. It sets the internal clock that governs both sleep and mood, so getting outdoors into natural light, particularly early in the day, helps keep that rhythm steady. In the largest study of its kind, an Australian-led analysis of more than 85,000 people found that greater daytime light exposure was associated with a lower risk of depression, and more light at night with a higher risk (Burns et al., 2023). For a body kept indoors by illness or fatigue, even sitting by a window or stepping outside for a few minutes counts. Sleep rests on the same rhythm: pain, medication, and worry all disturb it, and a poorer night makes the next day harder to carry, so protecting the conditions for rest is part of the same work.

The second move is to work with your energy rather than against it. In a well-bodied person, exercise is straightforwardly good for mood; in a body managing pain, fatigue, or illness, the same advice can land as one more demand you cannot meet. The evidence is still encouraging. An Australian-led umbrella review of 97 systematic reviews found physical activity associated with reductions in depression, anxiety, and distress across adult populations, including people living with chronic disease (Singh et al., 2023). The words that matter are within your limits. The dose that helps is usually smaller than people expect, and gentle, regular movement that fits your energy does more than occasional effort that leaves you flattened for two days. Pacing is the partner skill: pushing to make the most of a good day often borrows against the next three, so spreading activity out, resting before you are empty rather than after, and treating energy as a budget rather than a test are not signs of giving up. They are how people protect the capacity they have.

The third move is not to carry it alone. Withdrawal is an understandable response to feeling unwell, but contact with people you trust is one of the steadier supports for mood, and even brief connection counts. For many people, a support group adds something that friends and family cannot: time with others who live with the same condition and do not need it explained. Some are run in person, some online, and your GP or specialist can often point you to one that fits. Professional support has its own place alongside this, not in competition with it. A 2023 systematic review and meta-analysis found cognitive and behavioural therapies were associated with improvements in depression and anxiety for people living with chronic physical conditions (Scott et al., 2023). Therapy does not make an illness disappear. What it can do is change your relationship to it, loosen the grip of the worry, and help you find a way to live alongside something that is not going away.

• The emotional weight of a long-term condition is not separate from the illness. Physical and mental health move through the same body systems and shape each other in both directions.

• Low mood or anxiety after a diagnosis is a recognised response to a real and ongoing load, not a sign of failing to cope. In Australia, around one in twelve adults lives with both a physical and a mental health condition.

• Much of what helps is small, repeatable, and works with the body rather than against it: settling the system through breath, light, and sleep; working with your energy through gentle movement and pacing; and not carrying it alone.

• Connection matters, including support groups of others who live with the same condition. Your GP or specialist can often help you find one.

• Psychological support sits alongside medical care, not instead of it, and is associated with improvements in mood and anxiety for people living with chronic conditions.

There is no right time to start looking after the emotional side of your health, which means there is no wrong one either. Some people want that support from the moment of diagnosis, when everything is new, and the ground feels unsteady. Others manage for a long while and reach for it later, when the weight has quietly accumulated. Both are reasonable. You do not have to wait until things feel unmanageable to be worth helping.

When you are ready, your GP is a good place to begin. They can talk through how you have been, prepare a Mental Health Treatment Plan if it would help, and point you toward what is available, whether that is a psychologist, a support group, or services connected to your condition. Your specialist may know of others. None of it asks you to face your health, in the body or the mind, on your own.

That, in the end, is the through-line. The fatigue and the worry, the symptom and the low mood, were never two separate things. They are one system carrying a heavy load, and they respond, gently and over time, to the same care.