Vienna researchers prove effectiveness of light therapy

Researchers at Vienna’s General Hospital AKH have investigated the biochemical processes involved in seasonal depression and proved the effectiveness of light therapy.

Winter depression

Long nights, dull light, frequent fatigue: most people aren’t exactly bursting with energy or activity in the cold season. Some are even affected by the so-called winter depression, also known as seasonally affective depression or SAD. Researchers estimate that around six per cent of Austrians suffer from SAD. “SAD patients sleep and eat too much, craving carbohydrates in particular because they provide energy quickly” – these are some of the symptoms described by Prof. Siegfried Kasper, head of the Clinical Department for Biological Psychiatry at the Vienna AKH.

Study on biochemical causes

One of the reasons is lack of light, which can cause depressive moods even in people not suffering from SAD. These moods are due to a lack of the neurotransmitter serotonin, also known as the “happy hormone” which is needed as a chemical transmitter of electrical impulses between nerve cells in the brain. The researchers also looked into the reasons for this lack.

The transporter protein 5-HTT controls serotonin availability in the synapses. In SAD patients this protein is hyperactive, pumping serotonin away from its “site of action” too quickly. These findings of four years of research were recently published in the American Neuropsychopharmacology journal.

Light therapy at the Vienna AKH

Exposure to bright light slows down the transporter function of 5-HTT. “Patients’ sense of well-being improves. A positive effect was found even in test subjects that did not have SAD,” says Dr. Matthäus Willeit, one of the authors of the study.

Through the eyes the light arrives at the very parts of the brain that are affected in SAD patients. People who suspect they might be suffering from SAD can turn to a special surgery at the AKH where they can borrow light therapy lamps for a short period of time. Patients are advised to sit next to the lamp once a day, carrying out everyday activities, at a light intensity of 3,000 lux. If the treatment has a positive effect patients are advised to buy their own lamp. Prices start at 200 euros.

Around 80 per cent of patients respond well to the therapy. “They feel better after a few days already, they have more energy and they eat and sleep less,” says Prof. Kasper. Taking walks on sunny days also increases the personal sense of well-being, of course.

A light café

The higher the latitude, the more people are susceptible to seasonal depression. SAD is particularly frequent in Scandinavia where there is only a few hours of daylight in winter. Four years ago a restaurant owner in Stockholm who suffers from SAD himself had the idea to open a “light café”. “The thought of receiving light therapy in a dreary hospital wasn’t exactly appealing,” says Martin Sylwan, owner of the “Iglo Ljuscafé”.

Guests sit in bright white rooms that are furnished completely in white and enjoy their breakfast or dinner at a light intensity of 3,000 lux. “The light café is a pleasant yet professional treatment alternative that will certainly not remain the only one of its kind,” says Dr Maj-Liz Persson, psychiatrist at Stockholm’s Karolinska Hospital.

Links

Vienna General Hospital (AKH) Clinical Department of Biological Psychiatry Study in the Neuropsychopharmacy journal Iglo-Ljuscafé