Depression: The Power of Mood

(4 of 5)

That could explain why drugs that improve serotonin chemistry don't always work on depression--and why Parkinson's and depression can feed on each another. Epilepsy, stroke and Alzheimer's, which, like Parkinson's, involve physical alteration of the brain, probably also affect that organ's ability to make or process neurotransmitters--not only serotonin and dopamine but also glutamate and norepinephrine, all of which may be involved in different forms of depression.

Most treatments for depression aim to restore the electrochemical imbalance that leads a depressed brain into warped thinking. The so-called tricyclic antidepressant drugs popular in the 1960s, for example, boosted the activity of the neurotransmitters serotonin and norepinephrine, and two other neurotransmitters, active throughout the body. That often relieved depression but caused side effects, including overwhelming sleepiness, blurred vision and dizziness. The drugs also proved potentially lethal when taken in overdose.

Then in the 1970s, neuropharmacologists realized that they could minimize side effects by focusing just on serotonin. Antidepressant drugs like Prozac, Paxil and Zoloft, known as selective serotonin reuptake inhibitors, or SSRIs, were developed to keep serotonin from being reabsorbed quickly into nerve cells when it is produced.

Meanwhile, electroconvulsive therapy (ECT), better known as shock treatment, resets the electrical state of the brain by inducing a seizure. (Despite ECT's lurid reputation, it involves mild doses of current and can be almost miraculously successful in patients whose depression will not yield to drugs.) Even old-fashioned, low-tech talk therapy can help adjust a patient's brain chemistry and lessen the severity of depression, especially in conjunction with other treatments.

Unfortunately, the research that may unravel the interplay between depression and other diseases has barely begun. Even though there is a strong statistical link between depression and epilepsy, for example, we know very little about how to treat depression in epileptics. And as Charney has noted, it hasn't been proved, in a rigorous, scientific sense, that treating depression will reduce the excess risks of complication or death from a coexisting illness.

But if depression treatments rebalance the biochemistry that worsens disease, there is every reason to expect that they will reduce its deadly impact. So Charney, Evans and other experts want to make physicians more aware of the intimate connection between depression and other illnesses. "When you only have roughly eight minutes with your primary doctor," says Lydia Lewis, president of the Depression and Bipolar Support Alliance, "it's kind of hard to get into the realm of depression. And when you go to see a specialist, the cardiologist is thinking just about your heart."

So while researchers hold conferences, do studies and write scholarly papers, Lewis has some more immediate advice for patients. "We need to get people to go in and ask these questions of their physicians. Bill Valvo could not agree more. "I think people are totally unaware of what's going on," he says, "and I'm convinced that education is a key part of what we need to be doing." The essence of that education: cure the mind, and you might just help save the body.