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Hyponatremia is a common phenomenon in psychiatry occurring as an adverse effect to drugs or following polydipsia. We performed a retrospective in-depth analysis of hyponatremia cases in a large unselected population of psychiatric inpatients. During a 3-year period, all cases of hyponatremia were identified among patients admitted to a large psychiatric state and university hospital by the institution's electronic laboratory database. Demographic, treatmentrelated, and laboratory data were obtained by consecutive chart review, respectively. Hyponatremia occurred in 347 (4.9%) of 7113 cases, of which the majority (78%) displayed only a mild manifestation. Symptoms were recorded in 28.8% of cases, already occurred in mild forms, and comprised gait impairment (45%, including falls), confusion (30%), sedation (26%), and dyspepsia (41%). Age, female sex, nonpsychiatric drug polypharmacyVparticularly with thiazides and/or angiotensinconverting enzyme inhibitorsVand diagnosis of a mood disorder were associated with more severe hyponatremia, respectively. The proportion of hyponatremic patients treated with venlafaxine, trazodone, carbamazepine, oxcarbazepine, and first-generation antipsychotics, respectively, was significantly higher in the hyponatremia sample than in the normonatremic population. This was, surprisingly, not the case with selective serotonin reuptake inhibitors or any other antidepressant drug class. We found prescription with second-generation antipsychotics to be significantly associated with less severe hyponatremia.Hyponatremia may be mainly attributed to the syndrome of inappropriate antidiuretic hormone secretion, as indicated by decreased serum osmolarity in our sample. Besides old age and female sex, treatment with certain drugsVrather than whole drug classesVcarries a substantially increased risk. ] is maintained within tight limits through a complex homeostatic system involving hypothalamic osmoreceptors and peripheral baroreceptors regulating water intake and urine output via changes in thirst and the neurohypophyseal secretion of the antidiuretic hormone arginine-vasopressin (AVP).8 Thus, excessive water intake or inappropriate release of AVP in the absence of osmotic stimuli, respectively are among the most common pathomechanisms of hyponatremia. The latter condition is known as the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and occurs, among an array of other causes, as an adverse effect of a large number of psychotropic and other drugs. 7,9,10 Above all, a wealth of case reports, casecontrol, and population-based studies have implicated antidepressants, such as tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), selective serotonin and norepinephrine reuptake inhibitors (SNRIs), and certain anticonvulsantsVmainly carbamazepine and oxcarbazepineV in hyponatremia of this origin. 11Y13 The most prevalent nonpsychiatric drugs associated with SIADH-induced hyponatremia are thiazide diuretics and angiotensin-converting enzyme inh...

Anosognosia is common in patients with Alzheimer disease (AD) even in early stages. Although neural correlates and the impact of cognitive dysfunctions have been described, possible psychodynamic processes such as a repressive coping style as described in other illnesses, have not been examined. Our study aimed to examine possible psychological influence factors on illness perception embracing a repressive coping style and cognitive functions in AD patients in the diagnostic process. Fifty-four subjects with mild AD diagnosed in our memory clinic were enrolled. Anosognosia was evaluated using a patient-caregiver discrepancy rating. All patients underwent comprehensive neuropsychological testing. In addition, characteristics of a repressive coping style were assessed. In total, 79.6% of our patients showed a lack of awareness at least to some degree. 33.3% of the patients were classified as repressors. Repressors and nonrepressors did not differ in cognition, or the unawareness score. Multivariate regression analysis showed that repressive coping style did not significantly contribute to anosognosia, but that verbal memory and naming ability had a strong influence. Although our data indicate that a high proportion of patients with mild AD show characteristics of repressive coping, this possible defense mechanism had no influence on the awareness of illness-related deficits measured by caregiver patient discrepancy.

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Recent data suggest that inhibitory pathways may be involved in the pathophysiology of depression and in the mode of action of some antidepressant interventions. The aim of the present study was to test whether vagus nerve stimulation (VNS) can affect motor cortex excitability. Measures of motor cortical excitability were probed by using single-pulse and paired-pulse transcranial magnetic stimulation at baseline, after 10 weeks of left VNS, and additionally, in an on-off paradigm in 10 patients with treatment-resistant unipolar depression. Ten weeks of VNS was associated with a selective and pronounced increase in intracortical inhibition, whereas no changes occurred in the on-off paradigm. These results suggest that VNS is capable of changing motor cortical excitability in patients with depression.