The spice saffron is being investigated as a possible treatment for depression and anxiety symptoms in adolescents, with an Australian trial showing some promising results.

Researchers at Murdoch University in WA tested the impact of a high-dose saffron supplement on nearly 70 Australian adolescents, aged 12 to 16, suffering from moodiness or mild anxiety.

For the eight week randomised, double-blind trial, the adolescents were given 14mg of patented saffron supplement (affron(r)) or a placebo twice daily.

Overall, the teens on the saffron treatment reported a 33 per cent improvement in their mood, compared to 17 per cent in people taking the placebo.

The active treatment was also associated with "superior" improvements in anxiety levels as measured by the Spielberger State-Trait Anxiety Inventory (STAI).

Psychologist and co-author Dr Adrian Lopresti says the study has shown saffron has the potential to be an effective treatment that has very few side effects.

"Saffron was particularly effective in reducing symptoms associated with separation anxiety, depression and social phobia, and participants reported a reduction in headaches over the eight weeks as well," said Dr Lopresti.

"Although cooking with large quantities of saffron may be prohibitively expensive, supplements are a far more cost effective way to ingest the spice. We are now working to identify the optimal dose needed to lift moods and how long the treatment can be used for," he said.

While saffron may improve someone's response to stress, Dr Lopresti noted it's better to identify and treat the cause of stress in the first instance.

The researchers are now investigating whether the combined use of saffron and a pharmaceutical antidepressant works better than an antidepressant alone, in adults with depression.

Results of the trial, funded by Pharmactive Biotech Products SL, are published in the Journal of Affective Disorders.