Suicidal thoughts are associated with platelet counts in adolescent inpatients.

OBJECTIVE: Platelets (PLT), which serve as the primary hemostatic indicator, can be used as a peripheral model for studying monoamine turnover in the brain. Therefore, they are attractive targets as circulatory biomarkers for the detection of psychiatric disorders. However, PLT counts have not been utilized as a peripheral biomarker of psychopathology. METHODS: This study was a retrospective analysis of PLT counts upon admission of 108drug-naïve adolescents hospitalized in an inpatient psychiatric department. PLT counts of patients with suicidal ideation (SI) were compared with those of nonsuicidal in patients (NSI) and those of 77 healthy adolescents, serving as a control group. The patients' disorders were diagnosed and classified by one of four American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM IV) diagnoses, that is, unipolar depression, bipolar depression, schizophrenia, and a pooled group of conduct and borderline personality disorders. RESULTS: Significantly higher PLT counts were observed in SI patients, as compared with NSI patients (300,200±53.3/mL vs. 253,900±53.2/mL, respectively; p=0.0001). A significant difference in PLT counts in SI patients, relative to the control group, was also noted (300,200±53.3/mL vs. 254,000±52/mL, respectively; p=<10(-26)). Finally, a significant difference in PLT counts was observed between conduct/borderline personality disorders patient with and without suicidal ideation (292,000±55/mL vs. 246,000±64/mL, respectively; p=0.001). CONCLUSIONS: PLT counts are higher in suicidal hospitalized adolescents than in nonsuicidal inpatients, as well as than in controls.

Protein synthesis inhibition before or after stress exposure results in divergent endocrine and BDNF responses disassociated from behavioral responses.

This study aimed to assess the effects of anisomycin, a protein synthesis inhibitor, on behavioral responses, brain-derived neurotrophic factor (BDNF) and TrkB mRNA levels, and circulating corticosterone in rats-when administered before or after initial exposure to a predator scent stress stimulus. Magnitude of changes in prevalence of anxiety-like behaviors on the elevated plus-maze and exaggerated startle reaction as well as corticosterone levels and mRNA BDNF and TrkB were compared in rats exposed to predator stress, microinjected with anisomycin before or after stress exposure. Administration of anisomycin before or after stress exposure reduced anxiety-like behavior in the elevated plus-maze and reduced the mean startle amplitude 7 days postexposure. Although the behavioral responses were similar when anisomycin was microinjected before or after stress exposure, the levels of mRNAs for BDNF and TrkB, which play a role in modulation of synaptic plasticity and the consolidation process, showed varying responses.

Homocysteine levels in newly admitted schizophrenic patients.

We previously found a marked elevation of plasma homocysteine in young male schizophrenic patients in hospital. It seemed important to determine if this finding is already present in newly admitted schizophrenic patients. Serum homocysteine levels were studied in 184 consecutively admitted schizophrenic patients and 305 control subjects from an employee screening program. Homocysteine levels were markedly increased in this population of newly admitted schizophrenic patients, especially in young males. Newly admitted male schizophrenic patients have elevated homocysteine levels that cannot be explained on the basis of poor hospital nutrition. Smoking may raise homocysteine by 1-2 microM/L but this is not a large enough effect to explain our findings.

Lithium inhibitable enzymes in postmortem brain of bipolar patients.

Despite considerable ongoing efforts at the epidemiological, genetic and molecular level, the etiology of bipolar disorder had not yet been elucidated. To study possible contributing components to the pathophysiology of this disorder, we have hypothesized that levels of enzymes inhibited by therapeutically relevant lithium ion concentrations in the brain of patients may differ from those in normal controls and may be involved in the etiology of the disorder. Three Li-inhibitable enzymes were studied in postmortem brain samples of bipolar patients and normal controls. The expression and function of the two enzymes that are obviously involved in signaling cascades, IMPase, involved in the second messenger system of the phosphatidylinositol cycle, and GSK-3, a mediator of an array of signaling cascades, were not found to be different in postmortem frontal and occipital cortex of bipolar patients and normal controls. Only PAP phosphatase protein levels, but not its mRNA levels or enzymatic activity, were found to be significantly decreased in frontal cortex of bipolar patients compared with normal controls.