A new clinical trial has shown that how people respond to treatment for Bipolar Disorder may be influenced by their weight and the overall quality of their diet, including whether they are eating a diet high in foods thought to contribute to general inflammation.

These are early results, but if replicated may mean that treatment of some mental health problems could benefit from the inclusion of dietary advice.

Bipolar Disorder (which used to be called 'manic depression') is characterised by episodes of mood swings, between being very up or very down with periods in between the two extremes.

The fact that there are two opposite sets of symptoms means that finding an effective treatment is difficult. While current medications are useful, they are better at targeting mania symptoms (the 'up' phase), leaving a lack of effective treatment for people experiencing depressive episodes.

Now a group of Australian, German and American scientists has shown those who have a high-quality diet, a less inflammatory diet, and/or a low BMI (Body Mass Index) may respond better to an add-on nutraceutical treatment provided as part of a clinical trial.

Lead researcher Melanie Ashton said, "If we can confirm these results, then it's good news for people with Bipolar Disorder, as there is a great need for better treatments for the depressive phase of Bipolar Disorder."

Researchers measured BMI at the beginning of the study and then measured depression and how a person is able to function in their day to day life. Researchers also rated whether a participant was improving and, if so, how much, over the next 20 weeks.

Participants filled in a questionnaire about what they usually eat over the year and researchers calculated a diet quality score, where good diets included a healthy diet with lots of fruit and vegetables, whereas poorer-quality diets had more saturated fat, refined carbohydrates and alcohol. These types of diets were then categorised as either anti-inflammatory or pro-inflammatory based on foods that affect inflammation.

What this means, if these results can be repeated in a larger trial, is that treatment for Bipolar Disorder would need to take into account what a person eats and their weight.

Commenting on the same, Professor Eduard Vieta said, "This is interesting work, which holds out the possibility that patients with Bipolar Disorder may benefit from a balanced diet. However, it is an early study, and we need more research before we can think of whether this might affect clinical practice".

The study was presented 31st Congress of the European College of Neuropsychopharmacology Conference.