Mental illness: Probing the causes of schizophrenia, depression and anxiety

New research identifies the brain chemicals and circuits involved in mental illnesses like schizophrenia, depression, and anxiety, giving potential new directions to their treatment. In addition, research with children shows that early-life depression and anxiety changes the structure of the developing brain. The findings were presented at Neuroscience 2011, the Society for Neuroscience’s annual meeting and the world’s largest source of emerging news about brain science and health.

One in 17 Americans suffer from a serious mental illness, such as schizophrenia, major depression, or bipolar disorder, making it one of the leading causes of disability. Yet science is only beginning to understand the underlying physical causes of these diseases.

It is difficult to identify the causes of schizophrenia, but research suggests that several physical, genetic, psychological and environmental factors interact and make people more likely to develop the condition. Current thinking is that some people may be prone to schizophrenia, but sometimes a stressful or emotional life event might trigger a psychotic episode. However, it is not known why some people develop symptoms while others do not.

There are some risk factors for schizophrenia that you cannot change.

Genetics
Brain development
Neurotransmitters
Infection
Pregnancy and birth complications
Head injury
Triggers

Today’s new findings show:

- Childhood anxiety and depression alter the way the amygdala connects to other regions of the brain. This finding may help explain how early life stress can lead to future emotional and behavioral issues (Shaozheng Qin, PhD, abstract 927.06).

- In animal studies, a link between two factors associated with schizophrenia, prenatal infection and impaired function of a molecule important in memory (Melissa Burt, abstract 763.11).

- Researchers have identified a brain chemical important to antidepressant response in mice. The findings may help in the design of therapies for major depression (Maha Elsayed, abstract 904.10).

- The connections between two specific areas of the brain - the prefrontal cortex and the dorsal raphe nucleus - may contribute to depression. Stimulating these circuits in rats had an antidepressant effect (Melissa Warden, PhD, abstract 306.15).

- An enzyme called STEP is elevated in the brains of people with schizophrenia. Mice lacking this chemical did not develop schizophrenia-like behaviors (Nikisha Carty, PhD, abstract 238.03).

"If we can fully understand the roots of mental illness in brain circuitry and systems, we may be able to develop better treatment targets for the millions suffering from these diseases," said press conference moderator Carol Tamminga, MD, of the University of Texas Southwestern, who is an expert on schizophrenia.