Sex differences, season of birth and platelet 5-HT levels in schizophrenic patients

The Impact of Seasonality on Mental Health Disorders: A Narrative Review and Extension of the Immunoseasonal Theory

The impact of weather on mental illness is widely debated, but the mechanism of this relationship remains unclear. The immunoseasonal theory suggests that in winter, a T-helper 1 (Th1) response predominates, impairing Prefrontal Cortex (PFC) control, which exacerbates symptoms of depression, while after it, in summer, a Th2 response predominates in immunologically prone individuals, activating cortical and mesolimbic centers, which can exacerbate symptoms of psychosis. In this paper, we aim to describe the validity of this theory through a narrative review of data related to weather and immunology in psychiatry. This review extends existing literature by integrating immunological findings with psychiatric seasonality research, offering a mechanistic perspective that links Th1/Th2 shifts to specific symptom exacerbations. Winter Th1 severity may worsen depression and anxiety, while summer Th2 dominance appears to be associated with exacerbations of schizophrenia, mania, impulsivity, and suicide risk. It is possible that the mechanism of Th1 response potentiation and deterioration of PFC function is common to most psychiatric entities and is nonspecific. This suggests that seasonal immune dysregulation may play a broader role in psychiatric disorders than previously recognized, challenging the idea that seasonality impacts only selected conditions. Characteristic dysfunctions within an individual determine further differences in clinical manifestations. The mechanism of Th2 potentiation may not be limited to mania and psychosis but may also be associated with increased impulsivity and suicide risk. If the immunoseasonal theory is confirmed, selected immunological markers could be used not only in the diagnosis of psychiatric exacerbations but also in predicting symptom fluctuations and tailoring treatment strategies. This could enable more personalized interventions, such as seasonally adjusted medication dosing or targeted anti-inflammatory therapies. While this mechanism seems plausible, further research, especially analyzing markers of inflammatory and anti-inflammatory responses, is needed to better understand and confirm it.

Platelet Serotonin Concentration Is Associated with Illness Duration in Schizophrenia and Chronological Age in Depression

OBJECTIVE

Impaired serotonergic neurotransmission has been implicated in the pathogenesis of depression and schizophrenia. Blood platelets have been used for years as a peripheral model of neuronal serotonin dynamics. The objective was to investigate platelet count and serotonin concentration in patients with depression and schizophrenia, in an attempt to ascertain their clinical usefulness.

METHODS

953 participants were included in the study, 329 patients with depression, 339 patients with schizophrenia and 285 healthy controls. ELISA was used to assess platelet serotonin concentrations.

RESULTS

There were no statistically significant differences among groups regarding age, total platelet count and serotonin concentration. Linear regression analyses revealed inverse correlations between platelet serotonin concentration and age of patients with depression and healthy individuals, as well as between platelet serotonin concentration and illness duration in patients with schizophrenia. In other words, longer illness duration in patients with schizophrenia, and higher age in patients with depression and healthy individuals was associated with lower platelet serotonin concentrations.

CONCLUSION

Platelet count and serotonin concentration did not prove to be of diagnostic value in differentiating patients and healthy individuals. However, illness duration in patients with schizophrenia may be associated with reduced concentrations of platelet serotonin.

Brain, blood, cerebrospinal fluid, and serum biomarkers in schizophrenia

Over the last decade, finding a reliable biomarker for the early detection of schizophrenia (Scz) has been a topic of interest. The main goal of the current review is to provide a comprehensive view of the brain, blood, cerebrospinal fluid (CSF), and serum biomarkers of Scz disease. Imaging studies have demonstrated that the volumes of the corpus callosum, thalamus, hippocampal formation, subiculum, parahippocampal gyrus, superior temporal gyrus, prefrontal and orbitofrontal cortices, and amygdala-hippocampal complex were reduced in patients diagnosed with Scz. It has been revealed that the levels of interleukin 1β (IL-1β), IL-6, IL-8, and TNF-α were increased in patients with Scz. Decreased mRNA levels of brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), neurotrophin-3 (NT-3), nerve growth factor (NGF), and vascular endothelial growth factor (VEGF) genes have also been reported in Scz patients. Genes with known strong relationships with this disease include BDNF, catechol-O-methyltransferase (COMT), regulator of G-protein signaling 4 (RGS4), dystrobrevin-binding protein 1 (DTNBP1), neuregulin 1 (NRG1), Reelin (RELN), Selenium-binding protein 1 (SELENBP1), glutamic acid decarboxylase 67 (GAD 67), and disrupted in schizophrenia 1 (DISC1). The levels of dopamine, tyrosine hydroxylase (TH), serotonin or 5-hydroxytryptamine (5-HT) receptor 1A and B (5-HTR1A and 5-HTR1B), and 5-HT1B were significantly increased in Scz patients, while the levels of gamma-aminobutyric acid (GABA), 5-HT transporter (5-HTT), and 5-HT receptor 2A (5-HTR2A) were decreased. The increased levels of SELENBP1 and Glycogen synthase kinase 3 subunit α (GSK3α) genes in contrast with reduced levels of B-cell translocation gene 1 (BTG1), human leukocyte antigen DRB1 (HLA-DRB1), heterogeneous nuclear ribonucleoprotein A3 (HNRPA3), and serine/arginine-rich splicing factor 1 (SFRS1) genes have also been reported. This review covers various dysregulation of neurotransmitters and also highlights the strengths and weaknesses of studies attempting to identify candidate biomarkers.

Serotonin hormonally regulates lacrimal gland secretory function via the serotonin type 3a receptor

Tears are extracellular fluid secreted from the lacrimal gland (LG). Tears consist of a dynamic tri-layered film composed of secretions from the LG, Meibomian gland, and conjunctival goblet cells. The LG secretes the aqueous component of the tear, the Meibomian gland secretes the lipid component, and conjunctival goblet cells secrete mucin. The regulation of LG activity via the autonomic nervous system has been recognized as fundamental to maintaining aqueous tear flow. Here, we describe the role of a hormone, peripheral serotonin, in tear secretion. We found that blood serotonin concentration, changed by feeding a diet deprived of the serotonin precursor tryptophan, correlated with tear secretion, and that a sustained decrease in serotonin resulted in LG atrophy and autophagy. The combination of a decrease in serotonin with the interruption of autonomic neural stimuli to the LG preceded these alterations. Furthermore, we found that the serotonin type 3a receptor expressed in LG acinar cells is involved in tear secretion via intracellular calcium mobilization. Our findings demonstrate that hormonal regulation by serotonin, in cooperation with the autonomic nervous system, regulates tear secretion.

Theranostic Biomarkers for Schizophrenia

Schizophrenia is a highly heritable, chronic, severe, disabling neurodevelopmental brain disorder with a heterogeneous genetic and neurobiological background, which is still poorly understood. To allow better diagnostic procedures and therapeutic strategies in schizophrenia patients, use of easy accessible biomarkers is suggested. The most frequently used biomarkers in schizophrenia are those associated with the neuroimmune and neuroendocrine system, metabolism, different neurotransmitter systems and neurotrophic factors. However, there are still no validated and reliable biomarkers in clinical use for schizophrenia. This review will address potential biomarkers in schizophrenia. It will discuss biomarkers in schizophrenia and propose the use of specific blood-based panels that will include a set of markers associated with immune processes, metabolic disorders, and neuroendocrine/neurotrophin/neurotransmitter alterations. The combination of different markers, or complex multi-marker panels, might help in the discrimination of patients with different underlying pathologies and in the better classification of the more homogenous groups. Therefore, the development of the diagnostic, prognostic and theranostic biomarkers is an urgent and an unmet need in psychiatry, with the aim of improving diagnosis, therapy monitoring, prediction of treatment outcome and focus on the personal medicine approach in order to improve the quality of life in patients with schizophrenia and decrease health costs worldwide.

Platelet serotonin concentration and depressive symptoms in patients with schizophrenia

Depressive symptoms seem to be frequent in schizophrenia, but so far they have received less attention than other symptom domains. Impaired serotonergic neurotransmission has been implicated in the pathogenesis of depression and schizophrenia. The objectives of this study were to investigate platelet serotonin concentrations in schizophrenic patients with and without depressive symptoms, and to investigate the association between platelet serotonin concentrations and symptoms of schizophrenia, mostly depressive symptoms. A total of 364 patients were included in the study, 237 of which had significant depressive symptoms. Significant depressive symptoms were defined by the cut-off score of 7 or more on Calgary Depression Rating Scale (CDSS). Platelet serotonin concentrations were assessed by the enzyme-linked immunosorbent assay (ELISA). Prevalence of depression in patients with schizophrenia was 65.1%. Schizophrenic patients with depressive symptoms showed lower platelet serotonin concentrations (mean±SD; 490.6±401.2) compared to schizophrenic patients without depressive symptoms (mean±SD; 660.9±471.5). An inverse correlation was established between platelet serotonin concentration and depressive symptoms, with more severe symptoms being associated with lower platelet serotonin concentrations. Depressive symptoms in schizophrenic patients may be associated with reduced concentrations of platelet serotonin.

Platelets: A possible glance into brain biological processes in schizophrenia

Schizophrenia is a severe mental disorder, characterized by behavioral, emotional and cognitive disturbances, which commonly follows a chronic course. Diagnostic accuracy, management plans, treatment evaluation and prognosis are dependent on relatively subjective assessments. Despite extensive research and improvement in imaging technology, as well as modern genetic and molecular methodologies, the biological basis of this disease is still unclear. Therefore, there is a need for objective and valid biological markers. Platelets have often been used as a model in neurobiological research. The accessibility of platelets and their similarities with neurons turns them into an attractive candidate to search for biological markers for diagnosis and for unraveling pathophysiological processes relevant to the etiology of brain disorders, including schizophrenia. The present review addresses the main changes in platelet physiology observed in schizophrenia and its response to antipsychotic medication. We summarize numerous studies demonstrating impaired metabolism, uptake and receptor kinetics of schizophrenia-relevant neurotransmitters, abnormalities in membrane derived phospholipids and polyunsaturated fatty acids, as well as dysfunctions in the mitochondria. These changes fit with the various hypotheses raised for the etiology of schizophrenia, including the dopamine-glutamate hypothesis, the autoimmune hypothesis, the polyunsaturated fatty acid hypothesis and the impaired energy metabolism hypothesis. Despite extensive research in platelets, no conclusive reliable biomarker has been identified yet. This review suggests that the clinical heterogeneity and the biological complexity of schizophrenia lead to the inevitable conclusion that biomarkers will be identified only for subgroups characterized according to the different diagnostic criteria. Moreover, any biomarker would have to be an array of interrelated factors or even a set of several such arrays.

Suicide attempt, smoking, comorbid depression, and platelet serotonin in alcohol dependence

The risk of suicide in patients with alcoholism increases if alcoholism is related to comorbid depression. Both alcoholism and suicidal behavior are associated with reduced serotonin (5-hydroxytryptamine [5-HT]) function. Because suicide is enormous public health problem worldwide, to prevent suicide attempts, it is important to find peripheral marker of suicidal behavior. The aim of this study was to assess whether platelet 5-HT concentration is altered in alcoholic patients with or without suicide attempt. Platelet 5-HT concentration was evaluated in 397 male and 108 female ethnically homogenous medication-free patients with alcoholism, subdivided according to smoking status, comorbid depression, and a history of suicide attempt and in 450 male and 139 female healthy control (nonsuicidal) subjects. Suicide attempt was assessed by two measures: according to the score 4 on the item 3 from the Hamilton Rating Scale for Depression and according to the Structured Clinical Interview regarding suicidal attempt during lifetime. Both male and female patients with alcoholism who were nonsmokers had significantly lower platelet 5-HT concentration than the corresponding healthy subjects. Multifactor analyses of variance revealed the significant effects of alcoholism and smoking, but the lack of significant effects of suicide attempt, sex, or comorbid depression, and no interactions between variables, on platelet 5-HT concentration. Platelet 5-HT concentration did not differ significantly between suicidal patients compared with nonsuicidal patients with alcoholism. Because the results from the present study showed similar platelet 5-HT values between patients with or without a history of suicide attempt, our data did not support the hypothesis that platelet 5-HT concentration might be used as a peripheral marker of the pronounced suicidal behavior in alcoholism.

Platelet serotonin concentration and monoamine oxidase type B activity in female patients in early, middle and late phase of Alzheimer's disease

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder with unclear aetiology. Cognitive impairment in AD might be associated with altered serotonergic system. The aim of the study was to determine platelet serotonin (5-HT) concentrations and platelet monoamine oxidase type B (MAO-B) activity in patients with different severity of AD. Platelet 5-HT concentrations and MAO-B activity were determined spectrofluorimetrically in 74 female patients with AD (NINCDS-ADRDA, DSM-IV-TR criteria), subdivided according to the Mini Mental State Examination (MMSE) scores in three groups with a) 23 patients in early (MMSE scores 19-24), b) 23 patients in middle (MMSE 10-18), and c) 28 patients in late (MMSE 0-9) phase of AD, and in 49 age-matched healthy women. Platelet 5-HT concentrations and MAO-B activity were similar between all patients with AD and healthy subjects, but were significantly lower in patients in the late phase of AD than in other phases of AD, and in healthy controls. The significant correlations were found between MMSE scores and platelet 5-HT concentrations, MAO-B activity and age. Lower platelet 5-HT concentration and MAO-B activity in the late phase of AD suggested that these markers might indicate severity and/or clinical progress of AD.

Platelet serotonin concentration and suicidal behavior in combat related posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is a serious and global problem, a psychiatric disorder that frequently occurs with different comorbidities, and is associated with a high suicide rate. Pathophysiologically, both PTSD and suicidal behavior are related to disturbances in the central serotonergic system. Serotonin (5-hydroxytryptamine, 5-HT) controls emotional behavior, anxiety, impulsivity and aggression, and nearly all known antidepressants and antianxiety drugs affect 5-HT transmission. Platelet 5-HT can be used as a limited peripheral marker of the central serotonergic synaptosomes, since it is related to particular basic psychopathological characteristics of several psychiatric disorders. Platelet 5-HT concentration has been reported to be similar in PTSD subjects and healthy controls, but suicidal patients across different psychiatric diagnoses have reduced platelet 5-HT concentration. This study examined platelet 5-HT concentration by the spectrofluorimetric method in male subjects: 73 suicidal and 47 non-suicidal veterans with current and chronic combat related PTSD, 45 suicidal and 30 non-suicidal comparative non-PTSD subjects and 147 healthy men. The presence of suicidal behavior (score=0, non-suicidal; scores > or =1, suicidal) was assessed with the Hamilton Depression Rating Scale-17 (HDRS). Platelet 5-HT concentration was significantly lower in suicidal PTSD and non-PTSD patients compared to non-suicidal patients or healthy controls. Since the majority of patients scored very low on item 3 of HDRS, no significant correlation between suicidal scores and platelet 5-HT concentration was found. These results show that reduced platelet 5-HT concentration is related to suicidal behavior in PTSD, and suggest that platelet 5-HT concentration might be used as a peripheral marker to predict suicidal behavior across psychiatric diagnoses.

The influence of daylight exposure on platelet 5-HT levels in patients with major depression and schizophrenia

Platelet serotonin (5-HT) can be used as a limited, peripheral model for the central 5-HT synaptosomes. Altered platelet 5-HT concentrations have been associated with psychiatric disorders like depression and schizophrenia. The aim of the present study was to compare platelet 5-HT concentrations during long, medium and short period of natural daylight exposure in a large number of medication-free male and female schizophrenic and depressed patients and sex-matched healthy controls. Platelet 5-HT concentration was determined spectrofluorimetrically in 240 (97 female, 143 male) schizophrenic and 258 (153 female, 105 male) nonpsychotic, nonsuicidal depressed medication-free patients and 328 (149 women, 179 men) healthy subjects during periods with short (<12), long (>12) and medium (average 12) hours of the natural daylight. Platelet 5-HT concentration was significantly lower in women compared to men in all groups. Healthy male subjects had significantly higher (p=0.011) platelet 5-HT concentrations during long compared to medium period. There were no significant differences (p>0.05) in platelet 5-HT concentration between different periods in healthy women. The significant increase in platelet 5-HT values were found in female (p=0.01) and male (p=0.029) depressed patients during long compared to short period. There were no significant associations between platelet 5-HT concentrations and different periods in both male and female schizophrenic patients. The results indicate the sex-related differences in the serotonergic system. The alterations of platelet 5-HT concentrations, observed across period with different durations of daylight exposure, point to a direct or indirect effect of light on peripheral 5-HT system that could be related to different sensitivity of the pineal gland to light and/or melatonin influence on 5-HT metabolism.

Lower levels of whole blood serotonin in obsessive-compulsive disorder and in schizophrenia with obsessive-compulsive symptoms

It has been reported that some schizophrenic patients suffer from obsessive-compulsive symptoms (OCS), and clozapine treatment is quite often associated with an occurrence/increase of OCS in schizophrenic patients. The aim of the study was to explore whether differences would exist in the clinical symptomatology and the whole blood serotonin (5-HT) concentrations in patients with obsessive-compulsive disorder (OCD), schizophrenic patients with and without OCS (S+OCS, S-OCS), and clozapine-treated schizophrenic patients with and without clozapine-induced OCS (CLZ+OCS, CLZ-OCS). We found that S+OCS patients (n=15) showed significantly lower scores on the Hamilton Anxiety Scale (HAMA), but similar levels of compulsions and obsessions using Yale-Brown Obsessive-Compulsive Scale (YBOCS) as compared to the patients (n=35) with OCD. S+OCS patients scored significantly lower on the Positive and Negative Syndrome Scale (PANSS) but higher on the Hamilton Depression Scale (HAMD) compared with S-OCS patients (n=19). However, CLZ+OCS patients (n=15) suffered from dominant compulsions but fewer obsessions compared with the OCD and S+OCS patients. OCD, S+OCS and CLZ+OCS groups had significantly lower levels of whole blood 5-HT than did the healthy volunteers (n=15), S-OCS and CLZ-OCS groups. It suggests that alterations in serotonin metabolism may be a common biological characteristic of OCS in OCD as well as in schizophrenia.

Two different Alzheimer diseases in men and women: clues from advanced neural networks and artificial intelligence

BACKGROUND

Studies of the gender-related differences in the clinical presentation of Alzheimer's disease (AD) have focused on specific aspects of the disease (eg, circulating metabolites, cognitive capacity, or epidemiologic trends).

OBJECTIVE

This study accounts for several descriptors of the disease simultaneously, providing a multidimensional analysis of a cohort of patients with AD.

METHODS

Our analysis was conducted using self-organizing maps (SOMs). The high number (60) of independent variables (clinical, demographic, biochemical, and neuropsychological) observed in the study patients defines a complex and high-dimensional input space that can be processed by SOMs. Without supervision, SOMs examine nonlinear relations among the variables and cluster observations so that topologic relationships between variables correspond to the similarity of their distribution. Through such nonlinear autoclustering, subsets of observations (ie, clusters of subjects) can be identified in which essential information is concentrated. Each subject is identified by particular values of the variables (the record), and a specific set of variable values (the codebook) defines a distinct class.

RESULTS

The study sample included 211 patients with mild to moderate AD (143 women, 68 men; mean [SD] age, 71.9 [7.2] years). All patients were assigned to 3 macroclasses-called A, B, and C-on the basis of matrix codebook neighborhoods. In terms of vectorial distance between codebooks, class A and B were quite similar, whereas the separation between class C and classes A and B was evident. The SOM distribution of values of variables across the output matrix did not show any specific pattern for most of the considered characteristics. However, we found only male patients in class C. This class distinction was not substantially changed when sex was removed from the database. Male and female patients were comparable with respect to dementia severity, demographic characteristics, psychiatric and behavioral symptoms, indicators of physical disability, and general health status.

CONCLUSIONS

SOMs indicate nonlinear multifactorial interactions among the descriptors of the features of AD that seem to be linked to sex and would have been missed by traditional statistical analysis. This finding may offer a novel epidemiologic rationale for research into different pathogenic mechanisms in men and women with AD.

Platelet serotonin and plasma prolactin and cortisol in healthy, depressed and schizophrenic women

Serotonin (5-hydroxytryptamine, 5-HT) is involved in the regulation of hypothalamic-pituitary-adrenal axis (HPA) activity and prolactin (PRL) secretion. The present study examined the relationship between platelet 5-HT and plasma cortisol and PRL concentrations in 20 schizophrenic, 25 depressed, and 25 healthy women. At the time of blood sampling, the schizophrenic and depressed patients had been drug-free for at least 7 days. Platelet 5-HT, plasma cortisol and PRL concentrations were determined by spectrofluorimetric, radioimmunoassay and immunoradiometric methods, respectively. Platelet 5-HT concentration was significantly higher in schizophrenic patients than in depressed patients or in healthy controls, while it was significantly lower in depressed patients than in healthy controls or in schizophrenic patients. Plasma cortisol levels were significantly increased both in schizophrenic and in depressed patients compared with values in healthy controls. Values of plasma PRL were similar across groups. A significant correlation was found between platelet 5-HT and plasma cortisol, and platelet 5-HT and plasma PRL concentrations in healthy controls, but not in schizophrenic or depressed patients. There was no significant relationship between plasma PRL and cortisol levels in any of the groups. Our data, although obtained on peripheral biochemical markers, indicate that depression and schizophrenia are characterized by disturbed 5-HT transmission and dysregulated HPA axis activity.

Long-term sertraline treatment and peripheral biochemical markers in female depressed patients

Serotonergic system is implicated in the pathogenesis of depression. Peripheral biochemical markers, platelet serotonin (5-HT) and platelet monoamine oxidase (MAO) activity were determined spectrofluorimetrically at baseline and after 4 and 24 weeks of sertraline (a selective serotonin reuptake inhibitor (SSRI)) treatment in 15 female nonsuicidal, nonpsychotic patients with major depression and compared with 15 drug-free healthy women. The aim of the study was to determine the effects of 4 and 24 weeks of sertraline treatment on platelet 5-HT concentration and platelet MAO activity in depressed patients subdivided according to the treatment response into remitters, responders and nonresponders after 4 and 24 weeks of sertraline treatment based on the 70%, 50-69% and <49% reductions in baseline Montgomery-Asperg Depression Rating Scale (MADRS) scores, respectively. Platelet 5-HT concentration was significantly lower in all depressed patients at baseline than in healthy subjects. Among patients, platelet 5-HT concentration or platelet MAO activity did not differ before treatment. There was no significant correlation between MADRS scores and peripheral biochemical markers. The limitation of the study was in a small number of patients, but its advantage was in a long-term (24 weeks) follow-up of both patients and healthy controls. Our results show that long-term sertraline treatment induced remission and response in 87% patients, decreased platelet 5-HT concentration after 4 and 24 weeks of treatment and decreased platelet MAO activity after 24 weeks and suggest that pretreatment values of platelet 5-HT and platelet MAO might not predict therapeutic outcome to sertraline treatment in female depressed patients.

Platelet 5-HT concentration and comorbid depression in war veterans with and without posttraumatic stress disorder

BACKGROUND

The serotonergic system is implicated in the pathophysiology of posttraumatic stress disorder (PTSD) and depression. The present study focused on platelet serotonin (5-HT) concentration and symptoms of comorbid depression in war veterans with or without PTSD.

METHODS

PTSD and depression were evaluated using Clinician Administered PTSD Scale, Davidson Trauma Scale, Montgomery-Asberg Depression Rating Scale and Hamilton Anxiety Scale. Sixty-five male drug-free war veterans (48 with PTSD and 17 without PTSD) and 65 age- and sex-matched healthy controls were studied.

RESULTS

Comorbid depression occurred in 54 and 31% of war veterans with PTSD and without PTSD, respectively. Platelet 5-HT concentration was similar in the groups of depressed and nondepressed war veterans with or without PTSD and healthy controls. Platelet 5-HT concentration was found to differ between war veterans with various degrees of appetite loss. A positive correlation was observed between platelet 5-HT concentration and severity of appetite loss in veterans with PTSD. There was no relationship between platelet 5-HT concentration and severity of other symptoms of PTSD or depression.

LIMITATIONS

War veterans included in the study were outpatients.

CONCLUSIONS

War veterans with PTSD had a high incidence of comorbid depression, that was not related to platelet 5-HT concentration. The marked relationship between platelet 5-HT concentration and severity of appetite loss, suggested that 5-HT system is involved in the regulation of appetite, at least in depressed war veterans with PTSD.

Altered platelet serotonin 5-HT2A receptor density but not second messenger inositol trisphosphate levels in drug-free schizophrenic patients

The 5-HT2A receptor binding parameters using [3H]ketanserine and its intracellular signal inositol 1,4,5 trisphosphate (IP3) concentrations were determined in platelets from schizophrenic patients so as to assess differences with respect to a control group and to a standardized antipsychotic drug treatment. Seventy-five antipsychotic-free patients with a DSM-IV diagnosis of paranoid schizophrenia were included in the study. Blood samples were collected before the onset of antipsychotic treatment (baseline values) and after 3 weeks of treatment. Antipsychotic-free schizophrenic patients showed significantly increased basal 5-HT2A densities in comparison to the control group, together with a significantly increase (23%) in the 5-HT2A binding density in those patients treated with risperidone. These changes could be attributed to an up-regulation of 5-HT2A receptors caused by previous treatment with antipsychotic drugs, which is consistent with the chronic effect of 5-HT2A antagonists to up-regulate the number of binding sites. With regard to second messenger IP3 concentrations, basal concentrations in schizophrenic patients were not significantly different from control values, nor was there any significant difference between basal vs. posttreatment values. These results are possibly related to failure of second messenger systems of 'translating' extracellular messages generated presynaptically into effective neurotransmitter signals in schizophrenic patients.

The effects of paroxetine and tianeptine on peripheral biochemical markers in major depression

Depression is related to the alterations of the central serotonergic system and some antidepressants achieve their therapeutic effects through alteration of serotonin (5-HT) (re)uptake. Peripheral biochemical markers, platelet and serum 5-HT concentrations, platelet monoamine oxidase (MAO) activity, plasma levels of cortisol and prolactin (PRL), were investigated in patients with major depression before and after 4 weeks of treatment with paroxetine (an inhibitor of 5-HT uptake) or tianeptine (a stimulator of 5-HT uptake). Study was open, single center and included female depressed patients, 21 treated with tianeptine (37.5 mg/day) and 15 treated with paroxetine (20 mg/day), and 11 drug-free healthy women (controls). Before treatment, depressed patients as a group had significantly higher serum 5-HT and cortisol concentrations than healthy controls. There were no differences in the other biochemical markers. Response to antidepressant treatment was estimated according to the 50% fall in the initial scores of Hamilton Depression Rating Scale (HAMD) after 4 weeks of treatment. Good therapeutic response was observed in 47% and 45% patients treated with paroxetine and tianeptine, respectively. Paroxetine treatment induced significant decrease in platelet 5-HT concentrations in both responders and nonresponders, while no alterations in platelet 5-HT values were found in tianeptine-treated patients. There was a subgroup of depressed patients in paroxetine-treated group with high pretreatment platelet 5-HT concentration and later poor therapeutic response to paroxetine treatment. Serum 5-HT values, platelet MAO activity or plasma cortisol or PRL levels were unchanged after both treatments. The results suggest that pretreatment platelet 5-HT levels, but not other peripheral biochemical markers, might predict therapeutic outcome at least in paroxetine-treated patients.

Platelet serotonergic markers in posttraumatic stress disorder

The neurobiological basis of posttraumatic stress disorder (PTSD) is believed to involve alterations in different neurotransmitter systems, and recent studies elucidated the role of serotonin (5-hydroxytryptamine, 5-HT) in PTSD. The data on the role of 5-HT have been obtained using blood platelets as a peripheral model for central serotonergic neurons. The reports suggested that platelet 5-HT concentration and monoamine oxidase (MAO) activity might serve as biological, even trait, markers for particular mental disturbances. Since the data on the peripheral serotonergic markers in PTSD subjects are controversial, the aim of the study was to determine platelet 5-HT concentration and platelet MAO activity in war veterans with PTSD, war veterans who did not develop PTSD, and in war veterans who were prisoners of war and developed PTSD. Platelet 5-HT concentration and MAO activity did not differ significantly between war veterans with or without PTSD, and prisoners of war with PTSD. Clinician-Administered PTSD Scale (CAPS) scores did not differ between war veterans with PTSD and prisoners of war, but Montgomery-Asberg Depression Rating Scale (MADRS) scores were significantly higher in prisoners of war who developed PTSD than in war veterans with PTSD. There was no significant correlation between platelet 5-HT concentration or platelet MAO activity and CAPS or MADRS scores within these groups. Platelet 5-HT concentration was slightly higher and platelet MAO activity slightly lower in prisoners of war with PTSD, than in all other groups. These findings suggest that platelet 5-HT concentration and platelet MAO activity are not altered in three drug-free groups--war veterans who did or did not develop PTSD, or in prisoners of war with PTSD--and that these platelet serotonergic markers are not associated with symptoms of PTSD or comorbid depression.

Prolonged impact of pubertal serotonin treatment (hormonal imprinting) on the later serotonin content of white blood cells

The first encounter between the developing receptor and its target hormone establishes the hormonal imprinting which is needed for the normal function of the cell. In the presence of foreign-however able to bind-molecules, faulty imprinting develops with lifelong consequences. Hormonal imprinting influences not only the receptors, but also the later hormone production of cells. The critical time of hormonal imprinting is the perinatal period, however it can be executed sometimes (in continuously differentiating cells) also at puberty. As in earlier experiments single neonatal serotonin treatment caused a life-long alteration of white blood serotonin content in female rats, the early (10-19 day) and late (8 weeks) effect of single pubertal serotonin treatment was studied presently, by using flow cytometry. In contrast to the earlier (neonatal) results, pubertal treatment caused a radical reduction of serotonin content in male's lymphocytes, monocytes, granulocytes and mast cells, independent on the time of study. The effect in females was rather increasing, however uncertain. The experiments call attention to the possible different effects of neonatal and pubertal hormonal imprinting and to the imprintability of blood cells in adolescence.

Psychophysiology of post-traumatic stress disorder

In general, the results of psychophysiologic research on PTSD support the presence of a variety of autonomic, sensory, and cognitive processing differences between individuals with and without the disorder. The findings are diverse and include heightened responsiveness to trauma reminders; exaggerated startle; increased conditionability and autonomic responsiveness to aversive, high-intensity stimuli; and elevated tonic or baseline physiologic activity. Increased sensitivity of the central nervous system is suggested by electrophysiologic evidence for a failure to habituate to redundant information, over-responsiveness to novel information, and reduced cortical responsiveness to overstimulation. Cognitive processing abnormalities are suggested by electrophysiologic evidence for a reduced ability to attend to task-relevant information and increased attention to task-irrelevant, trauma-related information in individuals with PTSD. Some findings, such as the heightened physiologic and P300 response amplitude responses to trauma-related stimuli and increased HR response to loud tones, have been highly replicable and appear to be as reliable as any biologic finding in the psychiatric literature. Other findings, such as increased eye-blink startle responses and tonic or baseline physiologic activity, have been less consistently replicated and have led investigators to explore how stressful or threatening experimental contexts might produce phasic alterations in the psychophysiology of individuals with PTSD. We hope that the broad range of psychophysiologic investigations and findings in PTSD will inspire others to consider possible applications of these methodologies to their own clinical and research endeavors.

Season of birth, gender and negative symptoms in schizophrenia

The aim of this study was to ascertain whether the symptom profile distinguishes between schizophrenic patients born in the winter and early spring and those born in other seasons. The sample consisted of 204 patients with a DSM-III-R diagnosis of schizophrenia who had been hospitalized for acute psychotic decompensation. Symptom ratings were based on the Positive and Negative Syndrome Scale (PANSS). The use of demographic and anamnestic data as dependent variables did not detect any season-of-birth effect. In contrast, clear gender-specific differences emerged from the comparison focusing on symptom dimensions and clinical subtype. Female patients born in the winter and early spring had higher scores on the PANSS negative scale and anergia factor whereas male patients born in other seasons had higher scores on the PANSS anergia factor. In addition, we found a gender-specific association between season of birth and clinical subtype. Most paranoid female patients were born in the non-winter months whereas, among men, a slightly higher percentage of paranoid patients were born in winter months. These results suggest that gender plays a role in modulating the effect of the season of birth on symptoms of schizophrenia.