European Neuropsychopharmacology (v.14, #4)

Elevation of the cortisol/dehydroepiandrosterone ratio in schizophrenia patients by Michael Ritsner; Rachel Maayan; Anatoly Gibel; Rael D Strous; Ilan Modai; Abraham Weizman (267-273).
Dehydroepiandrosterone (DHEA) and its sulfate derivative DHEA-S are neurosteroids, produced in the brain, and neuroactive steroids, produced in the adrenals and affecting the brain. We compared the ratios of serum cortisol/DHEA or DHEA-S in schizophrenia patients with normal subjects, and determined the correlation of these ratios with psychopathology and distress. Early morning plasma concentrations of DHEA, DHEA-S, and cortisol were determined by radioimmunassay in 40 medicated schizophrenia inpatients, and 15 healthy subjects with similar age and sex distribution. Subjects were assessed for psychopathology using the Positive and Negative Syndrome Scale (PANSS) and the Montgomery and Asberg Depression Rating Scale (MADRS), anxiety, anger, emotional and somatic distress levels. Schizophrenia inpatients demonstrated significantly higher levels of state and trait anxiety, anger expression index, emotional and somatic self-reported distress scores. Cortisol/DHEA and cortisol/DHEA-S ratios were significantly higher in schizophrenia patients than in healthy comparison subjects. Both ratios correlated positively with age and duration of illness; cortisol/DHEA-S ratio also showed positive association with age of illness onset. When age, illness duration and age of onset were controlled, cortisol/DHEA-S ratio significantly correlated with severity of depression (MADRS, r=0.33, p=0.048), state and trait anxiety (r=0.43, p=0.008 and r=0.40, p=0.014, respectively), trait anger (r=0.41, p=0.012), angry temperament (r=0.46, p=0.004), anger expression index (r=0.36, p=0.033), and hostility (r=0.42, p=0.010). No significant association was found between these ratios and severity of psychopathology, and type or dosage of antipsychotic agents. Thus, elevated cortisol/DHEA and/or cortisol/DHEA-S ratios in schizophrenia patients are positively associated with higher scores for anxiety and anger, depression and hostility, age and age of onset/duration of illness, but are independent of severity of psychopathology (PANSS) and antipsychotic treatment.
Keywords: Dehydroepiandrosterone; Dehydroepiandrosterone sulfate; Cortisol; Neurosteroids; Schizophrenia;

The problem of antidepressant-resistant depression has necessitated finding ways of augmenting the actions of currently existing antidepressants. The present studies investigate the possibility of synergistic interactions between nitric oxide (NO) synthase inhibitors and antidepressants in the mouse forced swim test (FST), a pre-clinical test of antidepressant activity. Treatment with a behaviourally subactive dose of the NO synthase inhibitor N G-nitro-l-arginine (l-NA) (3 mg/kg) augmented the behavioural effect of the tricyclic antidepressant imipramine. In a similar fashion l-NA (3 mg/kg) augmented the effect of the selective serotonin re-uptake inhibitor (SSRI) fluoxetine but not the noradrenaline re-uptake inhibitor, reboxetine in the FST. The interaction observed between l-NA and fluoxetine generalised to other selective serotonin re-uptake inhibitors, namely, sertraline and citalopram in the FST. Treatment with a subactive dose of the neuronally selective NO synthase inhibitor, 7-nitroindazole (30 and 50 mg/kg), augmented the behavioural effects of imipramine and fluoxetine, respectively. Thus inhibition of NO synthase enhances the activity of antidepressants that work via a serotonergic mechanism in the FST. The results of the present investigation support a view that antidepressant effects, or enhancement of such effects in the FST, may be elicited via NO synthase inhibition. Furthermore, these data raise the possibility that inhibition of NO synthase could be used as a strategy to enhance the clinical efficacy of serotonergic antidepressants.
Keywords: Nitric oxide synthase; N G-nitro-l-arginine; 7-Nitroindazole; Selective serotonin re-uptake inhibitor; Antidepressant; Forced swimming test;

Regional mRNA expression of a second tryptophan hydroxylase isoform in postmortem tissue samples of two human brains by Peter Zill; Andreas Büttner; Wolfgang Eisenmenger; Brigitta Bondy; Manfred Ackenheil (282-284).
Tryptophan hydroxylase (TPH) as rate limiting enzyme in the biosynthesis of serotonin plays a major role as candidate gene in several psychiatric disorders. Recently a second TPH isoform (TPH2) was identified in mice, which was exclusively expressed in the brain. We investigated whether the mRNA of the human homologue of this new TPH2 isoform is expressed in the human brain but not in peripheral tissues. The study was performed with postmortem specimen obtained from two subjects who died on cardiovascular failure. TPH2 mRNA levels were determined by quantitative real time RT-PCR. TPH2 mRNA was exclusively present in the human brains but not in the investigated peripheral tissues. Our finding may open up new research strategies for the analysis of the repeatedly observed disturbances in the serotonergic system in patients suffering from several psychiatric disorders.
Keywords: Tryptophan hydroxylase; Postmortem; mRNA; Gene expression; Quantification; Brain;

Effects of acute and repeated administration of a cholinesterase inhibitor on timing behaviour by Pascale C Bouger; Laura Spowart-Manning; Andre Ferrara; Bernard H Schmidt; Franz-Josef van der Staay (285-294).
It has been hypothesised that a leftward shift in the response distribution obtained in the peak interval (PI) procedure is a characteristic of cognitive enhancement in which mental processes are speeded. Metrifonate, a cholinesterase inhibitor with reported cognitive enhancing properties in many animal models of learning and memory, was tested in the PI procedure. Acute administration of 3 and 60 mg/kg but not 1 and 30 mg/kg in fully trained rats shifted the response distribution to the right, whereas subchronic administration of 10, 30 or 50 mg/kg during task acquisition had no effect on timing behaviour. On the basis of the present data, it can be concluded that the effects of a cognition enhancer in the PI procedure cannot be predicted from the scalar expectancy theory (SET). Furthermore, SET does not appear to be an appropriate tool for analysing the acquisition of timing behaviour.
Keywords: Cholinesterase inhibitor; Metrifonate; Peak interval procedure; Scalar expectancy theory; Timing behaviour;

Impulsivity related to brain serotonin transporter binding capacity in suicide attempters by Mats B Lindström; Erik Ryding; Peter Bosson; Jan-Anders Ahnlide; Ingmar Rosén; Lil Träskman-Bendz (295-300).
Altered monoaminergic activity has earlier been associated with violent suicidal behaviour. In this study whole brain binding potential of the serotonin transporter (5HTT) and dopamine transporter (DAT) was measured by single photon emission computerised tomography (SPECT) in 12 patients after a serious suicide attempt and in 12 age, sex and season matched healthy controls. Clinical and temperamental assessments were analysed for possible associations with 5HTT and DAT.We found no significant 5HTT or DAT differences between patients and controls. In patients, but not in controls, there was a significant correlation between whole brain 5HTT and DAT. Impulsiveness according to the Marke Nyman Temperament (MNT) was significantly correlated to 5HTT in suicide attempters, but not in controls.Neither of the transporters could be regarded as a marker for serious suicidal behaviour. A previously discussed connection between serotonin and dopamine was replicated in this study. In suicide attempters, low 5HTT was associated with impulsivity and to some extent with depressive disorder—key factors for suicidal behaviour.
Keywords: Serotonin transporter; Dopamine transporter; SPECT; Suicide attempt; Impulsivity;

Zolpidem is not superior to temazepam with respect to rebound insomnia: a controlled study by Richard C.Oude Voshaar; Anton J.L.M. van Balkom; Frans G. Zitman (301-306).
This randomised controlled trial was conducted to compare zolpidem to an equivalent dose of temazepam with respect to subjective rebound insomnia after cessation of 4 weeks of treatment in chronic insomnia (zolpidem 10 mg, n=79; temazepam 20 mg, n=84). Both agents improved total sleep time (TST) as well as sleep onset latency (SOL) significantly during the 4 treatment weeks. Prevalence rates for rebound insomnia, defined as a worsening of TST or SOL of more than 40% compared to baseline, were 27% for TST and 53% for SOL in the Zolpidem condition and 26% and 58%, respectively, in the temazepam condition. No significant differences were found between both agents with respect to rebound insomnia, nor with respect to their efficacy or safety. We conclude that in clinical practice zolpidem has no advantages over temazepam with respect to rebound insomnia.
Keywords: Zolpidem; Temazepam; Sleep; Side-effect; Withdrawal;

Experimental studies have indicated that the central histaminergic system plays an important role in the inhibition of seizures through the stimulation of histamine H1 receptors. H1 receptor antagonists, including classical antiallergic drugs, occasionally may induce convulsions in healthy children and patients with epilepsy. The purpose of this study was to investigate the effects of antazoline and ketotifen (two H1 receptor antagonists) on the anticonvulsant activity of antiepileptic drugs against maximal electroshock (MES)-induced convulsions in mice. The following antiepileptic drugs were used: valproate, carbamazepine, diphenylhydantoin and phenobarbital. In addition, the effects of antiepileptic drugs alone or in combination with antazoline or ketotifen were studied on long-term memory (tested in the passive avoidance task) and motor performance (evaluated in the chimney test), acutely and after 7-day treatment with these H1 receptor antagonists. The influence of antazoline and ketotifen on the free plasma and brain levels of the antiepileptics was also evaluated.Antazoline (at 0.5 mg/kg), given acutely and after 7-day treatment, significantly diminished the electroconvulsive threshold. Similarly, ketotifen, after acute and chronic doses of 8 mg/kg markedly reduced the threshold for electroconvulsions. In both cases, antazoline and ketotifen were without effect upon this parameter at lower doses. Antazoline (0.25 mg/kg) significantly raised the ED50 value of carbamazepine against MES (both, acutely and after 7-day treatment). Furthermore antazoline (0.25 mg/kg) also reduced the anticonvulsant activity of diphenylhydantoin, but only after repeated administration, without modifying the brain and free plasma level of this drug. Moreover, valproate and phenobarbital did not change their protective activity when combined with antazoline. Ketotifen (4 mg/kg) possessed a biphasic action, acutely it enhanced the anticonvulsant action of carbamazepine and phenobarbital while, following 7-day treatment, reduced the antiseizure activity of carbamazepine. Ketotifen did not affect the free plasma or brain levels of antiepileptics tested. Only acute antazoline (0.25 mg/kg) applied with valproate impaired the performance of mice evaluated in the chimney test. Ketotifen (4 mg/kg) co-administered with conventional antiepileptic drugs impaired motor coordination in mice treated with valproate, phenobarbital or diphenylhydantoin. Acute and chronic antazoline (0.25 mg/kg) alone or in combination with antiepileptic drugs did not disturb long-term memory, tested in the passive avoidance task. Similarly, ketotifen (4 mg/kg) did not impair long-term memory, acutely and after 7-day treatment. However, valproate alone or in combination with chronic ketotifen (4 mg/kg) worsened long-term memory. The results of this study indicate that H1 receptor antagonists, crossing the blood brain barrier, should be used with caution in epileptic patients. This is because antazoline reduced the protective potential of diphenylhydantoin and carbamazepine. Also, ketotifen reduced the protection offered by carbamazepine and elevated the adverse activity of diphenylhydantoin, phenobarbital and valproate.
Keywords: Antazoline; Ketotifen; Antiepileptic drugs; Electroshock maximal; Drug interactions; Seizures;

How real are patients in placebo-controlled studies of acute manic episode? by Jitschak G Storosum; Annemarie Fouwels; Christine C Gispen-de Wied; Tamar Wohlfarth; Barbara J van Zwieten; Wim van den Brink (319-323).
Objective: To determine whether the results from placebo-controlled studies conducted in patients with manic episode can be generalised to a routine population of hospitalised acute manic patients. Methods: A list of four most prevalent inclusion and the nine most prevalent exclusion criteria was constructed for participation in previous randomised-controlled trials (RCTs). On the basis of this list, a consecutive series of 68 patients with 74 episodes of acute mania who had been referred for routine treatment were retrospectively assessed to determine their eligibility for a hypothetical but representative randomised controlled trial. Results: Only 16% of the manic episodes would qualify for the hypothetical trial (male episodes 28%, female episodes 10%), whereas 37%, 20% and 27% of the manic episodes would have to be excluded because they did no fulfil one, two or at least three of the inclusion or exclusion criteria. The most common exclusion criterion was “no use of contraceptives”. If this criterion was not taken into account, 28% of the male episodes and 33% of the female episodes would qualify for inclusion in the hypothetical study. Apart from the use of contraceptives, no significant differences between male and female episodes were observed in the reasons for exclusion: 11% suicidal ideation, 29% prior mood stabilising medication, 1% depot medication, 22% other axis I diagnosis, 27% internal disease somatic disease, 5% neurological disorder, 15% alcohol use disorder and 10% drug use disorder. Conclusion: Only a small percentage acute manic episodes in a routine mental hospital seem to qualify for a standard placebo-controlled RCT. It could be argued, however, that certain exclusion criteria (e.g. no use of contraceptives) are not very likely to reduce the external validity of a standard RCT. In contrast, some other exclusion criteria (e.g. comorbid alcohol and drug use disorders) may have resulted in an overestimation of the efficacy of anti-manic medications. These notions should be taken into account when evaluating the results of RCTs in bipolar patients with an acute manic episode.
Keywords: Manic episode; Placebo-controlled; Contraceptives;

Interactions between dopaminergic neurotransmission and cholecystokinin (CCK) in the CNS may be important in the pathogenesis of psychotic disorders and substance abuse. In this study, the effect of coadministration of the selective CCK receptor antagonists devazepide and L-365,260 (for selectively blocking CCK1 and CCK2 receptors, respectively), on the effect of amphetamine on the rat exploratory behavior, and on sensitization of locomotor response to amphetamine, were studied. Amphetamine (0.5 mg/kg) increased exploratory activity in the exploration box for 5 consecutive testing days, while devazepide (10 μg/kg) blocked and L-365,260 (10 μg/kg) enhanced amphetamine-induced stimulation of activity. Devazepide coadministration prevented the development of sensitization to amphetamine, while coadministration of L-365,260 with amphetamine potentiated the locomotor effect of a challenge dose of amphetamine. These results suggest that endogenous CCK, released during exploratory activity, shapes behavioral responses to amphetamine by acting on both receptor subtypes, and modulates the development of sensitization to amphetamine.
Keywords: Amphetamine; CCK; Devazepide; L-365,260; Exploratory behavior; Sensitization;

The effect of famotidine addition on olanzapine-induced weight gain in first-episode schizophrenia patients: a double-blind placebo-controlled pilot study by Michael Poyurovsky; Vered Tal; Rachel Maayan; Irit Gil-Ad; Camil Fuchs; Abraham Weizman (332-336).
Olanzapine treatment is associated with substantial weight gain. In this double-blind placebo-controlled study we evaluated whether the H2 antagonist famotidine may prevent/attenuate olanzapine-induced weight gain. Fourteen first-episode DSM-IV schizophrenia patients were randomly allocated to receive either famotidine (40 mg/day, n=7) or placebo (n=7) in addition to olanzapine (10 mg/day) for 6 weeks. All patients completed the trial. Patients in both groups showed a similar increase in body weight (olanzapine/famotidine: 4.8 (3.2) kg and olanzapine/placebo: 4.9 (1.6) kg, respectively; a between-group difference of 0.14 (1.3) kg). Four of seven (57.1%) patients in the olanzapine/famotidine group and three of seven (42.9%) in the olanzapine/placebo group gained at least 7% of their initial body weight, a cut-off for clinically significant weight gain. Famotidine addition was safe and well tolerated and did not interfere with olanzapine's therapeutic effect. In conclusion, famotidine (40 mg/day for 6 weeks) is not effective in preventing/attenuating weight gain in olanzapine-treated first-episode schizophrenia patients.
Keywords: Olanzapine; Histamine H2 antagonist; Weight gain; Famotidine; Schizophrenia;

Overnight metyrapone and combined dexamethasone/metyrapone tests in post-traumatic stress disorder: preliminary findings by Michael Kellner; Christian Otte; Alexander Yassouridis; Mildred Schick; Holger Jahn; Klaus Wiedemann (337-339).
Using overnight metyrapone and combined dexamethasone/metyrapone tests, hypothalamic–pituitary–adrenocortical (HPA) axis feedback regulation was characterised in 10 patients with post-traumatic stress disorder (PTSD) and 10 matched healthy comparison subjects. Significant treatment effects of both metyrapone and the combination of dexamethasone and metyrapone were observed for adrenocorticotropic hormone (ACTH), 11-deoxycortisol (11-DOC) and cortisol, but no differences between patients and comparison subjects emerged. Dose–response studies using metyrapone and glucocorticoid agonists are needed to further investigate HPA axis regulation in PTSD.
Keywords: PTSD; Metyrapone; Dexamethasone; HPA axis; ACTH; Cortisol;

Several studies postulated an interaction of clozapine with N-methyl-d-aspartate (NMDA) receptor-mediated transmission. We previously showed that acute clozapine application on rat prefrontal cortex (PFC) slices increased NMDA receptor-dependent long-term potentiation (LTP) in the prelimbic (PL) area. The present study explores the effects of subchronic clozapine treatment on LTP in the same brain area. After 21 days of treatment (30 mg/kg per day, via drinking water), rats were sacrificed and slices from the PFC were prepared for electrophysiological investigations. To this end, extracellular field potentials in the layer II–V pathway were recorded. In contrast to our previous study with acute application on the slice, subchronic clozapine treatment attenuated LTP as compared to non-treated animals. We interpret these findings to suggest that prolonged treatment with clozapine might result in a compensatory response to the acute facilitating action of clozapine on LTP-mediating processes.
Keywords: Subchronic clozapine treatment; Long-term potentiation; Prefrontal cortex;

Bright light therapy in seasonal affective disorder – does it suffice? by Edda Pjrek; Dietmar Winkler; Jürgen Stastny; Anastasios Konstantinidis; Angela Heiden; Siegfried Kasper (347-351).
Bright light therapy (BLT) has been proposed as treatment of choice for seasonal affective disorder (SAD). However, conventional antidepressants have also been found to be effective in this condition. We examined the psychopharmacologic medication in a clinical sample of 553 SAD patients, who had been treated with BLT, to assess the importance of drug treatment and to critically question the effectiveness of BLT. Forty-nine percent of our patients received psychopharmacologic treatment and about one third (35.4%) was treated with antidepressants, suggesting that BLT does not suffice as only antidepressant regimen for all SAD patients. Furthermore, our results show that only few patients with bipolar affective disorder were willing to accept long-term medication. Opposed to treatment guidelines, patients with several depressive episodes did not receive antidepressant maintenance medication or mood stabilizers more often than patients with only a few episodes.
Keywords: Seasonal affective disorder; Depression; Light therapy; Antidepressants; Mood stabilizers;