Chemical signature of manic depression discovered by scientists

February 5, 2008

People with manic depression have a distinct chemical signature in their brains, according to a new study. The research, published today in the journal Molecular Psychiatry, may also indicate how the mood stabilisers used to treat the disorder counteract the changes in the brain that it appears to cause.

Manic depression, which is also known as bipolar disorder, is a debilitating psychiatric condition characterised by alternating mania and depression, affecting about one in every hundred people worldwide. Although it is known that the condition can be treated relatively effectively using the mood-stabilising drugs lithium and valproic acid, the reasons why these treatments work are poorly understood.

The authors of the new study, from Imperial College London, the University of Cambridge, and the National Institutes of Mental Health in the US, hope that their research will enable a better understanding of the condition and of how it can be treated.

The researchers compared postmortem brain tissue samples of people with manic depression with those of age and gender matched controls. The samples were taken from the dorsolateral prefrontal cortex, which controls the processes involved in higher cognitive functioning. The researchers analysed these samples using Nuclear Magnetic Resonance spectroscopy and found that people with manic depression had different concentrations of chemicals in this area of the brain than those without.

The researchers also used rat models to see the effects of lithium and valproic acid on the metabolite makeup of non-bipolar brain tissue. They found that these drugs caused the opposite chemical changes to those seen in the bipolar brain tissue samples. Chemicals that were increased in the bipolar brain tissue were decreased in rats given the mood stabilising drugs, and vice versa.

The researchers’ findings lead them to believe that an upset in the balance of different neurotransmitters known as excitatory and inhibitory neurotransmitters, which are involved in sending signals in the brain, may be central to the disorder. The study also suggests that lithium and valproic acid work by restoring the balance of these neurotransmitters in the brain.

Levels of glutamate, an amino acid which acts as a neurotransmitter in the central nervous system, were increased in post mortem bipolar brain but glutamate / glutamine ratios were decreased following valproate treatment. Levels of another neurotransmitter, gamma-aminobutyric acid, were increased after lithium treatment and decreased in the bipolar brain. Both creatine and myo-inositol were increased in the post-mortem brain but depleted with the medications.

Dr Tsz Tsang, one of the authors of the study from the Department of Biomolecular Medicine at Imperial College London, said: “By identifying a distinct biochemical profile in patients with bipolar disorder, our new research provides a valuable insight into the origins and causes of the disease. Moreover, the changes we see in people’s metabolic signatures may give a target for drug therapy, allowing us to see how effective a drug is at correcting these changes.

“In this instance, we have already shown that the biochemical changes which valproic acid and lithium bring about in mammalian models represent almost a mirror image of the perturbations in bipolar disorder. This may provide a useful insight to the actions of these treatments and a basis for which to improve therapy in the future,” added Dr Tsang.

Source: Imperial College London

Explore further: New method predicts who will respond to lithium therapy

Related Stories

New method predicts who will respond to lithium therapy

March 20, 2017

For roughly one-third of people diagnosed with bipolar disorder, lithium is a miracle drug, effectively treating both their mania and depression. But once someone is diagnosed, it can take up to a year to learn whether that ...

Is the dark really making me sad?

March 14, 2017

The inhabitants of Rjukan in southern Norway have a complex relationship with the sun. "More than other places I've lived, they like to talk about the sun: when it's coming back, if it's a long time since they've seen the ...

Brain study identifies bipolar marker

March 10, 2017

People with the highest risk of developing bipolar disorder exhibit weak connections in the emotional areas of the brain, a world-first Australian study shows.

Another step in understanding antipsychotic medication

February 28, 2017

After much deliberation and anxiety, the family finally sought psychiatric help for their son. And the results were in a way, a relief. The doctors' verdict was that their child, their teenage son, was suffering from bipolar ...

Recommended for you

How the nervous system controls tumor growth

March 22, 2017

(Medical Xpress)—From the time it first comes online during development the nervous system begins to exact precise control over many biologic functions. In some cases, too much control. When it does, a little nerve-squelching ...

Surprising new role for lungs—making blood

March 22, 2017

Using video microscopy in the living mouse lung, UC San Francisco scientists have revealed that the lungs play a previously unrecognized role in blood production. As reported online March 22, 2017 in Nature, the researchers ...

Using a smartphone to screen for male infertility

March 22, 2017

More than 45 million couples worldwide grapple with infertility, but current standard methods for diagnosing male infertility can be expensive, labor-intensive and require testing in a clinical setting. Cultural and social ...

Weight-bearing exercises promote bone formation in men

March 22, 2017

Osteoporosis affects more than 200 million people worldwide and is a serious public health concern, according to the National Osteoporosis Foundation. Now, Pamela Hinton, associate professor in the Department of Nutrition ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

SDMike
not rated yet Feb 06, 2008
Are these findings a warning that consumption of creatine by athletes may lead to bipolar like behavior or at least disturbed mentation?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.