Depression

In 1976…

Having been attributed to everything from bile imbalances by the ancient Greeks, to a lack of meaning in one’s life by 20th century Freudian psychoanalytics, the term “Major Depressive Disorder” was officially in circulation by 1976. The ‘new’ moniker described a cluster of symptoms for which numerous biological, psychological and social causes and treatments had been proposed. Talk therapy, electroconvulsive (shock) therapy and social support were all common approaches to addressing depression that spoke to fundamentally different theories of its underlying causes.

Based on drug-trial observations in the 1950s, a dominant biological model suggesting that depression was caused by a chemical imbalance in neurotransmitters in the brain had become established by the mid-1970s. “However, there was still no cohesive or unified theory to explain the mechanism of action of antidepressant treatments,” says Dr. Pierre Blier, a world-renowned depression authority and Canada Research Chair in Psychopharmacology. “This was probably the largest deficit in our understanding that there was in the 1970s.”

Today…

Although our understanding of depression has evolved significantly, the exact nature and causes of the disease are still hotly debated as new lines of research continue to challenge our assumptions. However, evidence from neuroscience, genetics, and clinical investigation continue to demonstrate that depression is a brain disorder. “Where I believe we have gained some real insight,” says Blier, “is in realizing that there is no panacea for treating depression.” Recent neurological studies have indeed revealed that all of the brain’s major mood-regulating systems are interconnected. By pharmacologically enhancing one system, e.g., serotonin levels, other systems, e.g., dopamine, can be worsened. The current trend to increase the standard of care for people with major depression involves starting combination therapy from the outset. “Taking a multiple-medicine approach is common in almost all other diseases,” says Blier. “But we are still trying to break the barrier here in psychiatry.”

In the past 30 years, researchers have also learned quite a bit about how psychotherapy affects the brain. Brain-scanning studies have revealed that cognitive-behavioural therapy (CBT) is capable of positively modifying the same brain regions as commercial antidepressants. What’s more, these studies have surprisingly discovered that neurological changes induced by psychotherapy are maintained over time without pharmacological intervention.

Tomorrow…

Depression is one of the most common, debilitating illnesses in Canada. Over one million Canadians currently struggle with depression, and innovative research and treatments for depression are in high demand. While most people suffering from depression respond positively to pharmacological or psychotherapeutic therapy or simply recover naturally, a significant number of individuals are treatment-resistant. For these people, the work of researchers like Dr. Blier in vagus nerve stimulation (VNS), or Dr. Helen Mayberg of Emory University (USA) in deep brain stimulation (DBS), holds a great deal of promise. By virtue of either inactivating hyperactive areas or activating inactive areas of the central nervous system that are contributing to depression, these experimental treatments can relieve the symptoms of treatment-resistant depression through direct electrical stimulation. Drugs that speed-up the creation of new neurons in specific areas of the brain and that facilitate the formation of new connections between neurons throughout the brain are also in the early stages of development. “Depression may be a complex disorder, but we are finding bits and pieces of the puzzle every day,” says Blier.