To explore the biochemical indicators of the persons at high risk of suicide.

To achieve early screening of the persons at high risk of suicide.

Suicide ideation of new recruits was generally investigated with self-rating idea of suicide scale (SIOSS). Twenty-five recruits whose scores were more than 12 were recognized as the suicide ideation group. Another 25 recruits without suicide ideation were randomly selected as the control group. Saliva samples of each group were collected for biochemical analysis after one month and three months. The SIOSS was used again for evaluation of suicide ideation.

After one month, the concentrations of Ca, Mg, Amy and SA in saliva were demonstrated to be statistically different between the two groups. After three months, the concentrations of Ca, Mg, Amy and SA in saliva between the two groups showed no significantly difference. According to SIOSS results, only 7 persons of the original suicidal ideation group were recognized as suicidal ideation group, the other 18 people's SIOSS scores were less than 12. And the SIOSS scores of the control group (without suicidal ideation group) were also less than 12. There was no statistical difference in the three groups for comparison of salivary Ca, Mg, Amy and SA.

The biochemical indicators l of saliva lack specificity for suicidal ideation screening.

The author has not supplied his declaration of competing interest.