Metabolism and diet are linked to root of bipolar depression, say researchers

Iain Campbell, a researcher based at Edinburgh University, has a special perspective on bipolar depression. He lives with the condition and has lost family members who have taken their own lives because of their depression. It remains an intractable, devastating health problem, he says.

More than a million people in the UK have bipolar depression, of whom a third are likely to attempt suicide. Yet the condition’s roots remain unknown – despite significant efforts to understand them.

However, a major new approach to the illness has recently been adopted by psychiatrists to uncover its causes and highlight possible treatments. Rather than viewing bipolar depression as a mood disorder, it should be seen as a metabolic disturbance that can be tackled through diets and other interventions that can change bodily processes.

“We should be thinking of bipolar depression, not as a primary emotional problem, but as a malfunctioning of energy regulation in the body,” said Campbell, who has played a key role in setting up Edinburgh University’s Hub for Metabolic Psychiatry, which opened last week. “It is a very different way of thinking about mental illness.”

Backed by the Baszucki Foundation, a Canadian charity, and UK Research and Innovation, the national funding agency, the hub will investigate bipolar depression’s links to metabolic disorders, such as diabetes and obesity, and will also investigate how it is affected by disruptions to circadian rhythms.

“Systems involving energy, metabolism and light are all interlinked in our bodies and one outcome to their disruption is bipolar depression, we believe,” said Professor Danny Smith, head of the new Hub for Metabolic Psychiatry.

Bipolar depression was originally known as manic depression, a label that catches its progression, Smith added. “At times, people have no energy. At others, they simply have too much. They are manic. They don’t need sleep. They are really active and do things that are out of character. Psychiatrists will say to them: how are you feeling? In fact, they should be asking: what are you doing?”

One approach is developing metabolic treatments that could curtail their bouts of mania and lethargic depression, said Campbell. “Ketogenic diets, in which a person eats no carbohydrates but lots of fats, are quite common. They are used to cut weight but also to treat epilepsy in some cases. However, it is now becoming clear they can help alleviate bipolar depression.”

A recent study carried out at Edinburgh University involved 27 individuals with bipolar depression who were put on a keto diet for eight weeks.

“A third of them did very well. Their mood was more stable, they were less impulsive, and their depression lifted,” said Smith. “[Finding] out why some responded and others did not will be one of the first undertakings for researchers at the new hub.”

Other research will focus on the fact that many bipolar individuals suffer depressive episodes that peak in autumn and winter, while their mania increases in spring and autumn. “We all feel a bit gloomy in winter compared with summer but it is a very intense experience for bipolar people and it is a problem that emanates from disruptions to the circadian rhythms that control their internal body clocks,” said Smith.

“One patient told me that she knew she was becoming manic because she experienced a heightened sensitivity to colour and light. In other words, bipolar individuals appear to be more sensitive to light at certain times of the year. But why?”

One attempt to answer this question will involve the Edinburgh-led group in growing retinal cells – derived from bipolar people – in the laboratory. Scientists will then use them to see if they respond differently to light shone through them and impact on how they perceive and respond to light and changing seasons.

Other technological approaches will involve using radar sleep technology. These devices measure a person’s breathing, movement and heart rate and can tell when someone is awake or not and what stages of sleep they are going through.

“We are going to use these for very long periods, for 18 months or so, in bipolar people’s bedrooms. Whenever they become unwell, we can then look at how their sleep patterns were changing and so find ways that we might use to predict them becoming unwell in future – based on changes in their sleep patterns.

“In fact, there are a host of different approaches we can take to measure how sleep, circadian and metabolic factors might affect a person’s mental health – and we aim to track down the most important over the next few years.”