Learned Helplessness and the Switch for Depression

By torturing laboratory animals in various ways over the years, psychologists have documented in detail a phenomenon known as learned helplessness. Essentially, they have shown that if you subject some animals to pain that is beyond their control, they start assuming that all pain is beyond their control and take no measures to escape it even when they can; leave the door open and they still sit miserably in the room with the electrified floor. One key discovery is that animals vary in how long it takes to teach them helplessness, and how soon they unlearn it. Some dogs or mice are much more robust than others and will leap to escape as soon as they can, no matter how much misery you have inflicted on them first.

Some psychologists consider this a reasonable model of human depression. Part of the definition of depression, they say, is not taking measures to make yourself happier even when they are available. So as our understanding of brain physiology grows these psychologists have begun prying into the brains of animals in learned helplessness experiments. Here is the latest finding:

Scientists continue to search for the underlying genes and neurobiology that dictate our reactions to stress. Now, a study using mice has found a switch-like mechanism between resilience and defeat in an area of the brain that plays an important role in regulating emotions and has been linked with mood and anxiety disorders.

After artificially enhancing the activity of neurons in that part of the brain — the medial prefrontal cortex — mice that previously fought to avoid electric shocks started to act helpless. Rather than leaping for an open escape route, they sat in a corner taking the pain — presumably out of a belief that nothing they could do would change their circumstances.

I suppose what drives researchers to carry out these experiments is the hope that they will one day find a literal switch in the brain that could be stimulated or suppressed with drugs or implanted electrodes, banishing depression or other mental afflictions forever. I doubt this is possible without major side effects, like broad changes in personality, but I understand the attraction of the idea.

Some days I feel optimistic about the progress in brain science and its potential to provide real help for people with depression, anxiety, and other mental problems. Other days I shake my head and suspect that no matter how much we learn we will still be stuck with who we are, and that drugs that make us feel better will all turn out to have as many problems as the drugs we have used for millennia to achieve the same effect.