Pain, particularly chronic pain, is more than just a physical sensation; it is also a powerful emotional condition. It has the power of affecting everything from mood, behavior, and thought and has the potential of causing dependence, isolation, and even immobility in some cases.
Similarly, pain in these ways relate to depression, and can even be seen as a negative feedback loop of sorts. Pain can be depressing, and depression creates and exacerbates pain. This cycle can be a dangerous one. In fact, people afflicted by chronic pain are three times more likely to develop psychiatric disorders (most often anxiety or mood disorders) and people afflicted by depression are three times more likely to develop chronic pain.
Treating pain and depression through medication
Luckily enough, nearly every psychiatric medication can doubly be used as a pain medication. Antidepressants are seen as the most multifaceted of the psychiatric medications due to its analgesic effect when presented in lower doses (which may be independent of their effect on depression).
Tricyclics and selective serotonin reuptake inhibitors—commonly known as SSRIs—are the two principal types of antidepressants and each serves different roles in the treatment of pain. One tricyclic in particular, Amitriptyline (Elavil), has some sedative properties that can help people in pain. Amitriptyline is therefore commonly recommended as an antidepressant to be used as an analgesic.
SSRIs in comparison are usually not as effective as tricyclics at pain relief, but they are less risky than tricyclics because SSRI side effects are generally better tolerated by patients. Psychiatrists have been known to prescribe SSRIs—like fluoxetine (Prozac) or sertraline (Zoloft)—to be taken during the day and amitriptyline at night for patients experiencing pain.
The new “dual-action” drug venlafaxine (Effexor) is said to be of a higher caliber than either a sole tricyclic or a sole SSRI due to its ability to act on both neurotransmitters. Although many clinicians and researchers have come out in support of venlafaxine, their claims have gone widely unsubstantiated and the evidence on its effectiveness remains inconclusive.
Psychiatrists have also been looking into the potential effectiveness of the drug gabapentin (Nuerontin). Gabapentin serves mainly as an anticonvulsant drug, but it also blocks the activity of substance P, a neurotransmitter commonly seen in the regulation of pain and depression.
Specific disorders and how pain is exhibited
Depression and migraines often go hand in hand; more than 10% of Americans are affected by migraines. In a recent study conducted over the course of two years, physicians found that people who have had depression are three times more likely to have a migraine for the first time. Even more so, they found that those with a history of having migraines are five times more likely to develop depression.
A good illustration of the biological connections between physical pain and depression is exhibited in fibromyalgia. Common symptoms of fibromyalgia range from tenderness of certain pressure points and overall muscle aches, yet no signs of tissue damage. The pain centers of patients with confirmed fibromyalgia are highly active, according to their brain scans. The link between depression and fibromyalgia is actually much higher than other medical conditions. The link between these mood changes and pain is potentially sensitized drastically by a brain malfunction that possibly causes fibromyalgia.
This linkage between depression and pain is indicated by the configuration of the nervous system. The reception of pain signals are operated by brain pathways found in the limbic region. These pathways use serotonin and norepinephrine, two neurotransmitters that regulate mood. When regulation of mood no longer functions normally, depressive symptoms such as anxiety and hopelessness are augmented along with the pain. This bodes poorly for the patients afflicted because chronic pain as well as chronic depression, because both affect the nervous system, perpetuating the cycle of disorders.
Resources: American Academy of Pain Management www.aapainmanage.org