Michela Picchetti

Cognitive impairment in major depression

In the past decade, a growing bulk of evidence has accumulated to suggest that patients suffering from major depression (MD) present some cognitive disturbances, such as impairment in attention, working memory, and executive function, including cognitive inhibition, problem- and task-planning. If the results of short-term memory assessment in depressed patients are equivocal, a general consensus exists that memory problems are secondary to attentional dysfunctions, and reflect the inability to concentrate. Moreover, both unipolar and bipolar patients show evidence of impaired verbal learning that has been commonly interpreted as reflecting an inability to transfer information from short-term to long-term storage. According to some authors, there would be a gender-related as well age-related specificity of some disturbances. Depressed patients also show impairments of executive functions and their recent exploration through brain imaging techniques has recently permitted to formulate some general hypotheses on the possible involvement of different brain areas in MD.

Pharmacokinetics and pharmacodinamics of psychotropic drugs: effect of sex

Data on the specific effects of sex on pharmacokinetics, as well as tolerability, safety, and efficacy of psychotropic medications are still meager, mainly because only recently sex-related issues have attracted a certain degree of interest within the pharmacological domain. Therefore, with the present study, we aimed to provide a comprehensive review of the literature on this topic, through careful MEDLINE and PubMed searches of the years 1990-2012. Generally, data on pharmacokinetics are more consistent and numerous than those on pharmacodynamics. Sex-related differences have been reported for several parameters that influence pharmacokinetics, such as gastric acidity, intestinal motility, body weight and composition, blood volume, liver enzymes (mainly the cytochrome P450), or renal excretion, which may alter plasma drug levels. Sex-related peculiarities may also account for a different sensitivity of men and women to side effects and toxicity of psychotropic drugs. Further, some differences in drug response, mainly to antipsychotics and antidepressants, have been described. Further studies are, however, necessary to explore more thoroughly the impact of sex on the pharmacokinetics and pharmacodynamics of psychotropic drugs, in order to reach the most appropriate and tailored prescription for each patient.

Mitochondrial Alterations and Neuropsychiatric Disorders

Mitochondria are membrane-enclosed organelle found in most eukaryotic cells, where they generate the majority of the cells supply of adenosine triphosphate (ATP), used as a source of chemical energy. In addition, they are involved in a range of other processes, such as signalling, cellular differentiation, cell death, as well as the control of the cell cycle and cell growth. Mitochondria have been implicated in several neuropsychiatric disorders, in particular, depression, anxiety, schizophrenia, autism, and Alzheimers dementia. Furthermore, the presence of mutations at the level of mitochondrial or nuclear DNA (mtDNA and nDNA, respectively) has been linked to personality disorders, behavioral disturbances, thought alterations, impulsivity, learning impairment, cognitive failures until dementia. The aim of this paper is to review the literature on the relationship between psychiatric symptoms or syndromes and mtDNA mutations or mitochondrial alterations, while highlighting novel therapeutic targets for a broad range of disorders.

Decreased density of the platelet serotonin transporter in pathological gamblers.

Background/Aims: The aim of this study was to investigate the serotonin transporter (SERT), by means of the 3H-paroxetine ([3H]-Par) binding to platelet membranes, in patients affected by pathological gambling (PG), as compared with a similar group of healthy control subjects. Methods: Seventeen PG patients were selected amongst those who were drug-free and at the first psychiatric interview in a Department of Addiction. The diagnosis was assessed according to DSM-IV criteria and PG severity was measured by means of the South Oaks Gambling Screen. The platelet [3H]-Par binding was carried out according to a standardized method. The binding parameters, the maximum binding capacity (Bmax) and the dissociation constant (Kd), were obtained by means of the Scatchard analysis. Results: The Bmax values of PG patients were significantly lower than that of healthy subjects, while the Kd values were not different in the two groups. No significant effect of age, sex or psychiatric comorbidity on Bmax or Kd was observed; there were also no correlations between clinical and biological variables. Conclusions: PG patients showed a dysfunction at the level of the platelet SERT that would suggest the involvement of the 5-HT system in this condition.

Impulsivity, gender, and the platelet serotonin transporter in healthy subjects

The present study explored the possible relationships between impulsivity, gender, and a peripheral serotonergic marker, the platelet serotonin (5-HT) transporter (SERT), in a group of 32 healthy subjects. The impulsivity was measured by means of the Barratt Impulsivity Scale, version 11 (BIS-11), a widely used self-report questionnaire, and the platelet SERT was evaluated by means of the specific binding of 3H-paroxetine (3H-Par) to platelet membranes, according to standardized protocols. The results showed that women had a higher BIS-11 total score than men, and also higher scores of two factors of the same scale: the motor impulsivity and the cognitive complexity. The analysis of the correlations revealed that the density of the SERT proteins, as measured by the maximum binding capacity (Bmax) of 3H-Par, was significantly and positively related to the cognitive complexity factor, but only in men. Men showed also a significant and negative correlation with the dissociation constant, Kd, of (3H-Par) binding, and the motor impulsivity factor. These findings suggest that women are generally more impulsive than men, but that the 5-HT system is more involved in the impulsivity of men than in that of women.

Serotonin Receptors of Type 6 (5-HT6): From Neuroscience to Clinical Pharmacology

The serotonin (5-HT) receptors of type 6 (5-HT6) are quite different from all other 5-HT receptors, as they include a short third cytoplasmatic loop and a long C-terminal tail, and one intron located in the middle of the third cytoplasmatic loop. A lot of controversies still exist regarding their binding affinity, effects of 5-HT6 ligands on brain catecholamines, behavioral syndromes regulated by them, and brain distribution. In spite of the lack of information on metabolic pattern of the various compounds, some of 5-HT6 receptor ligands entered the clinical development as potential anti-dementia, antipsychotic, antidepressant and anti-obese drugs. The present paper is a comprehensive review on the state of art of the 5-HT6 receptors, while highlighting the potential clinical applications of 5-HT6 receptor agonists/antagonists.

Thermal balneotherapy induces changes of the platelet serotonin transporter in healthy subjects

Although the beneficial effects of balneotherapy have been recognized since a long time, a few information is available on the biological mechanisms underlying them and the subjective feelings of increased well-being and mood. The links between the serotonin (5-HT) system and mood prompted us to investigate the 5-HT platelet transporter (SERT), which is considered a reliable, peripheral marker of the same structure present in presynaptic neurons, in 20 healthy volunteers before (t0) and 30 min after (t1) thermal balneotherapy with ozonized water of Montecatini spa, as compared with a similar group who underwent a bath in non-mineral water. The SERT was evaluated by means of the specific binding of (3)H-paroxetine ((3)H-Par) to platelet membranes. Equilibrium-saturation binding data, the maximal binding capacity (Bmax) and the dissociation constant (Kd), were obtained by means of the Scatchard analysis. The results showed that, while Bmax values did not change in both groups, the Kd values decreased significantly at t1 only in those subjects who bathed in ozonized water. The results of this study, while showing a decrease of the dissociation constant (Kd) which is the inverse of affinity constant, of (3)H-Par binding to SERT in all subjects after balneotherapy and not in those bathing in normal water, suggest that SERT modifications may be related to a specific effect of ozonized water and, perhaps, also to the increased sense of well-being.

The Role of Platelet/Lymphocyte Serotonin Transporter in Depression and Beyond

A large amount of the data gathered in the last 50 years support the hypothesis that alterations of the serotonin (5-HT) neurotransmission play a crucial role in the pathophysiology of not only major depression (MD), but also of different neuropsychiatric disorders. Research in this field has been substantially promoted by the evidence that the reuptake protein (SERT), present in presynaptic neurons, is a key element in terminating the activity of the neurotransmitter in the synaptic cleft. For this reason, it was specifically targeted for the development of second-generation antidepressants, in particular of selective 5-HT reuptake inhibitors (SSRIs), with the aim of increasing the intrasynaptic 5-HT concentrations. Moreover, since a lot of studies showed that circulating platelets and, more recently, lymphocytes possess functional SERT proteins, they have been widely used as peripheral mirrors of the same structures located in the central nervous system. The presence of functional SERT in blood cells suggests strict relationships between the nervous and the immune system that need to be better clarified in MD, as well as the possibility of reciprocal modulation of the two systems by different drugs. This paper aims to review briefly the literature on the 5-HT hypothesis of depression with a major focus on the possible role of SERT in this disorder, while highlighting how recent data are more oriented on dimensional rather than nosological involvement of this structure in different conditions spanning from normality to pathology.

Plasma fluvoxamine levels and OCD symptoms/response in adult patients

In this study, we explored the possible relationships between plasma fluvoxamine levels and clinical features and/or response in adult obsessive–compulsive disorder (OCD) patients treated with this drug for 6 months.

The Rabbit Syndrome: State of the Art

INTRODUCTION The rabbit syndrome (RS) is a rare movement disorder generally associated with prolonged use of antipsychotics and characterized by inwilling, rhythmic, fast and fine movements of oral and masticatory muscles along the vertical axis of the mouth. PREVALENCE The prevalence of RS ranges between 1.5% and 4.4%; middle and elderly ages, the female gender, as well as past brain injuries are considered risk factors for its development. PATHOPHYSIOLOGY Although a dysbalance of the cholinergic and dopaminergic neurotransmission in the basal ganglia seems to be involved in the pathophysiology of RS, its precise mechanisms need to be clarified as yet. RELATIONSHIPS WITH ANTIPSYCHOTICS: Fifty cases of RS have been published up-to-now: 34 and 10 occurred during treatments with typical and atypical antipsychotics, respectively, while 6 seemed unrelated to these drugs. DIFFERENTIAL DIAGNOSIS The differential diagnosis between RS and tardive dyskinesias involving the mouth may be based mainly on the evidence that in these last conditions the movements of the mouth are less regular and slower and involve the tongue. Treatment strategy: The available data suggest that RS responds favourably to anticholinergic drugs and to the change of the antipsychotic.