Increased orexin levels in the cerebrospinal fluid the first year after a suicide attempt

BackgroundThe orexins (hypocretins) and cocaine and amphetamine regulated transcript (CART) are hypothalamic peptides involved in the regulation of sleep and appetite. We have previously shown that levels of both orexin-A and CART in the cerebrospinal fluid (CSF) are related to specific psychiatric symptoms.MethodsTen patients took part in lumbar punctures and psychiatric evaluations in conjunction to a suicide attempt and after 6 and 12 months. We measured CSF-orexin and CART using radioimmunoassays.ResultsMean CSF-orexin was significantly higher at the first and second follow-up than at the suicide attempt. In contrast, mean CSF-CART did not differ over time. Total SUAS scores, as well as ratings of CPRS item 66 (global illness) were significantly lower at follow-up. At one year, there was a significant negative correlation between the change in CSF-orexin and the change in total SUAS score.LimitationsThe number of patients who participated was relatively small.ConclusionsOur results support the hypothesis that orexin is involved in psychiatric symptomatology.