Increased concentrations of kynurenine (KYN) pathway metabolites have been associated to several groups of psychiatric disorders. As for suicide risk literature is still inconclusive due to the limited evidence.

to test the hypothesis of Increased concentrations of kynurenine as related to suicide attempter.

We aim to investigate the association between kynurenine pathway metabolites blood levels and suicidal behaviour, in affective disorder patients, in order to explore if kynurenine pathway metabolites could be potential diagnostic biomarkers.

We enrolled a sample of affective disorder patients and perform detailed diagnoses, as well as detailed assessment of suicidal behaviour using validated questionnaires. We also aim to follow-up individuals included in the current study.

Plasma KYN was assayed by high performance liquid chromatography in three groups: healthy volunteers (n=90), patients with mood disorders with a recent suicide attempt (n=44) and without (n=44) history of suicide attempt. Analysis of variance tested for group differences in KYN levels. Each was evaluated with psychometric scales. Patients were sampled for 10 cc of venous blood for assay. The preparation of blood samples and assay was processed by a specialist using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

Preliminary results will be presented as to shed light if KYN levels differed across groups. According to preliminary calculations we expect that KYN is higher in suicide attempters compared with non-attempters, who did not differ from healthy volunteers.

Our work-in-progress study suggests that KYN and related molecular pathways may be implicated in the precipitation of suicidal behavior.