On the Horizon

Our understanding of depression and bipolar disorder has changed radically since the mid-1990s, and we're likely to learn even more in the coming years. Right now, the following avenues of inquiry look promising.

Genes and treatments

Researchers are now pinpointing the genes involved in depression and elucidating their functions. For example, we now know that a variation at the gene known as G1463A causes low levels of serotonin, making you less responsive to drugs like SSRIs. If this work fulfills its promise, eventually doctors will be able to use genetic testing to predict which medication or therapy will help a particular person's depression. That new era is still years from making it into your doctor's office, but the science is evolving rapidly.

Diet and supplements

Could fish truly be a brain food essential to your mental health? The jury is out until larger, more rigorous studies take place, but some preliminary research suggests a link between inadequate intake of omega-3 fatty acids — which are found in such foods as tuna, salmon, and sardines — and depression and bipolar disorder.

In addition, the B vitamin folate may have an effect on mood because of its role in metabolizing certain brain chemicals. A study in 2000 found that 500 micrograms (mcg) of folic acid daily increased the effectiveness of Prozac in women (but not in men). However, larger trials are needed to confirm this finding.

New medications

Researchers and drug manufacturers are exploring a variety of new treatments for depression and bipolar disorder. One approach attempts to calm an overly active stress-response system, either by blocking the overproduction of corticotropin-releasing hormone (CRH) from the hypothalamus or by sopping up cortisol. Drug manufacturers are looking for agents that could accomplish these tasks.

Deep brain stimulation

Deep brain stimulation involves surgically implanting electrodes in the brain that are connected to a pacemaker-like device in the chest. This device sends tiny, weak electrical impulses to stimulate an area of the brain believed to play a role in depression. According to one small study, these techniques may be helpful when other therapies have failed. This therapy has been used successfully to treat Parkinson's disease. However, it is still experimental for people with depression.

Because surgery is necessary, if deep brain stimulation is eventually approved to treat depression, it will most likely be used only for people with serious depression who haven't been helped by a variety of other proven treatments.

Is it dementia or depression? In older adults who experience an intellectual decline, it's sometimes difficult to tell whether the cause is dementia or depression. Both disorders are common in later years, and each can lead to the other. It's not rare for a person with dementia to become depressed, and a depressed person may lose mental sharpness. The latter case is sometimes called the dementia syndrome of depression. People with this form of depression are often forgetful, move slowly, and have low motivation as well as mental slowing. They may or may not appear depressed. This syndrome responds well to treatments for depression. As mood improves, the person's energy, ability to concentrate, and intellectual functioning usually return to their previous levels. Although depression and dementia share certain traits, there are some differences that help distinguish one from the other: Decline in mental functioning tends to be more rapid with depression than with Alzheimer's or another type of dementia. Unlike Alzheimer's patients, people who are depressed are usually not disoriented. People with depression have difficulty concentrating, whereas those affected by Alzheimer's have problems with short-term memory. Writing, speaking, and motor skills aren't usually impaired in depression. Depressed people are more likely to notice and comment on their memory problems, while Alzheimer's patients may seem indifferent to such changes. Because there's no test that can reveal whether someone has depression or dementia, if you and your doctor aren't certain, it's worth trying a depression treatment. If depression is at the root, treatment can produce dramatic improvement.