In a patient group of 90 suicide attempters, 18% showed an impaired blood-CSF barrier; of these 16 patients, all but one were younger than 45 years. When compared with 105 healthy controls, a significant difference in impairment of the blood-CSF barrier, between patients and controls, was seen only in those younger than 45 years (z = -2.66; P < 0.01). Paracetamol intoxication was more common among those with an impaired blood-CSF barrier than among those without an impairment (Fisher's exact test, P = 0.00029). Paracetamol intoxication was the most common method of suicide attempt in patients with adjustment disorders. There was no significant association between alcohol and/or drug abuse and an impaired blood-CSF barrier (Fisher's exact test, P = 0.91977). There were no differences in IgG index between patients and controls. The hypothesis that a blood-CSF barrier leakage may be a confounding factor when assessing the levels of monoamine metabolites in the CSF did not receive any support.