Depression is cunning. Symptoms of depression can be complex and vary from person to person. In most cases, we recognise depression by symptoms such as low spirits, sadness, a feeling of hopelessness and loss of interest in things we used to enjoy, but the onset of depression is not always easy to notice or recognise.

Many people try to cope with their symptoms without realising they are unwell. Sometimes, it can take a friend or family member to point out that something is wrong. One needs to pay attention to the signals the body is sending out because depression has physical effects, as well. Although it may sound unusual, physical symptoms are common in the case of depression, and in fact, both unclear pain and everyday pain are often symptoms of depression.

A large proportion of patients with depression who seek help in primary healthcare institutions only report physical symptoms, which can make it difficult to diagnose depression. Physical pain and depression have a deeper biological link than simply cause and effect. The neurotransmitters serotonin and norepinephrine (biologically active substances that bind to receptors on other cells to carry nerve impulses from the synapse to the cell) affect both pain and mood. Insufficient regulation of these substances has been linked to both depression and pain, so it is worth paying attention not only to mood but also to physical symptoms.

• Sleep problems. Problems falling asleep or interrupted sleep (frequent waking up) are common in people suffering from depression.
• Chest pain. Such pain can be a sign of heart, lung or stomach problems but is sometimes a symptom of depression. Depression can also increase the risk of heart disease. In addition, people who have had a heart attack are more likely to suffer from depression.
• Fatigue and exhaustion. Fatigue and lack of energy for daily activities, even when you’ve had enough sleep and rest, can be a sign that you are depressed. Depression and fatigue together tend to worsen both conditions.
• Muscle and joint pain. Persistent pain can increase the risk of depression, and depression can cause pain because both conditions share chemical triggers in the brain. People with depression are three times more likely to feel regular pain.
• Gastrointestinal tract problems. Our brain and digestive system are closely linked, which is why many of us experience stomach pain or nausea when we are stressed or anxious. Depression can also cause nausea, indigestion, diarrhoea or constipation.
• Studies show that people with major depression are three times more likely to develop migraines, and people with migraines are five times more likely to develop depression.
• Back pain. Regular back pain can contribute to depression. And people who suffer from depression are four times more likely to have intensive, debilitating neck or back pain.

Although the diagnostic criteria for depression focus on emotional and vegetative symptoms, severe depression is also associated with painful physical symptoms such as the aforementioned headaches, back pain, stomach pain, joint pain and muscle pain. Given the fact that depression and pain share a common neurochemical pathway, depression and the associated physical symptoms that cause pain need to be treated together. Studies (1), (2) show that a treatment regimen for depression that does not address the physical symptoms and focuses only on the core emotional symptoms can lead to incomplete remission and a poorer treatment prognosis.

(1) Trivedi MH. The link between depression and physical symptoms. Prim Care Companion J Clin Psychiatry. 2004;6(Suppl 1):12-6. PMID: 16001092; PMCID: PMC486942.

(2) Denniger JW, Mahal Y, and Merens W. et al. The relationship between somatic symptoms and depression. In: New Research Abstracts of the 155^th annual meeting of the American Psychiatric Association. 21 May 2002 Philadelphia, Pa. Abstract NR251:68–69.