One is that stressful life events are a major cause of depression. The other is that an imbalance in neurotransmitters in the brain triggers depressive symptoms.

These beliefs were the basis for the drugs currently used to treat depression, and it appears they may both be incorrect.

Current antidepressants aim to boost neurotransmitters based on the popular molecular explanation of depression, which is that it's the result of decreased levels of the neurotransmitters serotonin, norepinephrine and dopamine.

The new research found strong indications that depression actually begins further up in the chain of events in the brain. Essentially, the medications have been focusing on the effect, not the cause.

The researchers also found powerful molecular evidence that quashes the long-held dogma that stress is generally a major cause of depression. The new research reveals that there is almost no overlap between stress-related genes and depression-related genes.