US scientists found that diabetic patients with the highest levels of depression, anxiety and stress were least successful in reducing their blood sugar.

A team from the Medical College of Ohio studied 18 adults with insulin-dependent diabetes.

Half of the participants received medical care and kept logs of their daily blood sugar readings.

The other half also learned relaxation techniques in 12 sessions, each lasting 45 minutes, and were encouraged to practice them twice a day at home.

The scientists report their findings in the journal Applied Psychophysiology & Biofeedback.

Four weeks after the treatment ended, the researchers were surprised to find no significant difference in blood sugar levels between those who received relaxation therapy and those who did not.

However, when they looked closer, they found evidence that relaxation training did benefit some patients - those not suffering from depression and anxiety.

Among 12 patients who were not depressed, those who practiced relaxation techniques lowered their blood sugar levels about nine per cent, with no change in those who did not.

Similarly, among nine patients who were not anxious, those who practiced relaxation techniques reduced their blood sugar levels by about 12%, with no change in those who did not.

'Daily hassle is too much'

Blood tests can monitor blood sugar

Dr Angele McGrady, one of the researchers, said: "Patients with symptoms of depression and frequent daily hassles may have found the demands of the treatment plan too hard and may have not adhered to recommendations for home practice of relaxation."

Other researchers have found that treatment with cognitive behavioral therapy (CBT) or serotonin reuptake inhibitor antidepressants can improve mood and blood sugar control in diabetics with depression.

The scientists plan to study the benefits of adding CBT or anti-depressants to relaxation therapy in diabetes treatment.

A spokesman for the British Diabetic Association said: "Any stress, emotional or physical can raise the blood glucose levels.

"Relaxation techniques like massage and yoga can help to reduce stress and as a result help to lower blood glucose levels.