Depression is Linked to Physical Pain Years Later

According to a new study by researchers at UCL (University College London), older people with pain are more likely to experience worsening depression symptoms up to eight years before the onset of pain. The study, published in the journal eClinicalMedicine, suggests that treating depression in this age group could help prevent or alleviate pain later in life.

How Pain and Depression are Linked

The researchers compared survey data from 3,668 adults over the age of 50 who frequently experienced moderate to severe pain with a similar-sized group of people without such complaints. In the pain group, they found that depressive symptoms increased rapidly in the eight years before the onset of pain, peaked at the onset of pain, and remained at a high level in the following years, while in the group without pain, depressive symptoms were less severe, less common, and relatively constant. The researchers observed a similar trend with loneliness, which increased both in the years before and after the onset of pain, but remained low and relatively constant among participants without pain. Although the cause of the pain could not be determined, most participants reported pain in their back, knee, hip, or foot.

Lead author Dr. Mikaela Bloomberg (UCL Epidemiology & Public Health) said: “It is well known that pain and depression are linked and reinforce each other. But we don’t know anything about the timing of these co-occurring conditions. Our study shows that depressive symptoms and loneliness worsen long before the onset of pain. This is important because it suggests that early mental health and social support may reduce or delay the onset of pain. Factors such as depression and loneliness can contribute to pain through various mechanisms. By triggering stress, they can increase inflammation, which can lead to pain. They can also increase sensitivity to pain by altering immune responses and deregulating our autonomic nervous system, the network of nerves that controls unconscious processes such as the “fight or flight” response.

“Our findings underscore the importance of looking at pain from more than just a biological perspective. Measures to promote mental health can also play an important role.” The study used data from 21 years of the English Longitudinal Study of Ageing (ELSA), in which a nationally representative sample of the population in England answers a variety of questions every two years. The research team found that the sharp increase in depressive symptoms among participants who experienced pain was greater among people with lower levels of education and wealth. According to the researchers, this is likely due in part to these individuals having fewer resources to support their mental health and pain management.

Quality of Relationships Important

The team explained that this finding shows that vulnerable populations with fewer socioeconomic resources need to be prioritized with accessible mental health programs and community support. The researchers also investigated whether there is a link between social isolation and pain experiences, but unlike loneliness, they found little difference in social isolation between the group with pain and the group without pain. While loneliness is a subjective feeling of a lack of social relationships, social isolation indicates an objective lack of contact with friends and family. The team suspected that the quality of relationships, rather than their quantity or the degree of social interaction, is important for alleviating pain and depression.

Three-quarters of the study participants in the pain group reported pain in their back, knees, hips, or feet. Of the remaining participants, 1.9% reported pain throughout their body, 0.5% reported mouth or tooth pain, and 20.7% reported pain in other areas. As a limitation of the study, the research team pointed out that the participants were predominantly white, reflecting the population of England in this age group. Future research should clarify whether the results are similar for younger groups and those with greater ethnic diversity. They pointed out that the survey data did not distinguish between pain and chronic pain. However, they obtained consistent results when they limited the analysis to participants who reported pain in consecutive surveys conducted two years apart, suggesting that the results also apply to chronic pain. The team took into account a variety of factors that could skew the results, including gender, age, year of birth, education level, wealth, long-term health conditions, physical activity, alcohol consumption, and smoking status of the participants.