Research suggests that anywhere from 30 to 50% of people with chronic pain also struggle with depression or anxiety.
Chronic pain isn’t just a physical condition—it’s an emotional one as well that has tremendous influence over a person’s thoughts and moods. People with chronic pain may isolate from others or be unable to achieve mobility they once had. Chronic pain isn’t just associated with physical injuries either, as it can stem from conditions like heart disease, arthritis, migraines, or diabetes.
Sometimes it can be difficult to assess whether chronic pain has led to depression, or vice versa. People with chronic pain are three times more likely to develop symptoms of depression or anxiety, and people with depression are three times as likely to develop chronic pain.2 Depression frequently can cause unexplained pain, such as headaches or back pain, and people who are depressed might struggle to improve or maintain physical health. In turn, chronic pain can lead to trouble sleeping, increased stress, or feelings of guilt or worthlessness associated with depression. These influences can create a cycle that is hard to break.
Although depression can further debilitate people with chronic pain, these people may be less likely to recognize and talk about symptoms of depression with their doctor. In fact, half of all depressed persons who visit the doctor only complain about physical symptoms. 4 Because both pain and depression make each other difficult to treat, it’s important to address both when evaluating treatment options.
https://www.psycom.net/depression.central.chronic.pain.html
Someone in pain from an injury may cut back on their activity because they’re afraid of being reinjured. If lack of activity keeps them from improving their physical condition, they may actually become deconditioned — and thus susceptible to injury, he explains. In another scenario, “Chronic pain may cause sleep problems, or feelings of helplessness and worthlessness related to missed work or financial woes. These can all lead to depression,” says Dr. Jimenez
https://health.clevelandclinic.org/why-chronic-pain-brings-you-down-how-to-feel-better/