Like the famous question, “What comes first, the chicken or the egg?” both depression and pain can be the other’s cause or effect. While depression can generate and amplify pain due to an imbalance in neurotransmitters, extended pain, in turn, can cause a person to become depressed.

Over 75% of patients with depression complain of physical pains and most are unaware of the fact that its chemical effects can aggravate chronic physical conditions and increase pain. Depression can precede and even predispose a patient to developing chronic pain because of the chemical imbalance it creates along with its hindrance with usual pain threshold and coping mechanisms.

Neurotransmitters-chemical substances, called serotonin and norepinephrine, are produced and regulated within in our brain to keep everyday pain sensations in sync by blocking or decreasing pain signals. However, when levels of serotonin or norepinephrine are decreased and unbalanced, which occurs with depression, the brain becomes incapable of processing the transmitted pain signals properly. Pain signals can be exaggerated and distorted.

Common symptoms of depression are feelings of gloom, decreased interest and pleasure, loss of or excessive appetite weight gain or loss, excessive or decreased sleep, agitation, loss of energy, worthlessness, guilt, decreased concentration or increased indecisiveness, memory loss, anxiety, irritability, thoughts of death or suicide attempt. Moreover, people with chronic pain and depression even more often show signs of irritability and anxiety rather than sadness.

On the other hand, people with a chronic condition such as osteoarthritis, rheumatoid arthritis or fibromyalgia, can become depressed because of increasing pain severity and episodes, interference with daily activity, a lack of response to treatment and stress. Being in pain can be very frustrating and discouraging.

While, pain and depression together are more prominent amongst women, it appears that these conditions can go hand-in-hand and lead to significant disability. The prognosis of combined depression and pain is poor compared to that for individuals with depression or pain alone.

Fortunately, research has shown that by increasing levels of either serotonin or norepinephrine in the brain with the use of anti-depressants, pain signals can be decreased and even blocked. Selective serotonin reuptake inhibitors (SSRIs), tricyclic anti-depressants, and especially serotonin and norepinephrine reuptake inhibitors (SNRIs), which are dual-acting anti-depressants that can increase both serotonin and norepinephrine, have proven capable of decreasing pain, while treating both depression and chronic pain. Because pain can induce depression and vice versa, these new dual-acting agents can provide physicians with safe and convenient treatments for these connected conditions.

While depression and pain seem to have the ability create an unbreakable vicious cycle, there is hope and there are ways to prevent and treat its reciprocal effects. Combined analgesics, anti-depressants with relaxation training, positive expectation, healthy attitude and even cognitive behavior therapy can break the cycle.