C. Barnas

Genetic polymorphisms for drug metabolism (CYP2D6) and tardive dyskinesia in schizophrenia.

In the present study, the occurrence of tardive dyskinesia (TD) in chronic schizophrenia patients was investigated in relation to pharmacogenetic polymorphisms. It is known that the metabolism of important neuroleptic drugs is influenced by polymorphisms of the CYP2D6 gene, which encodes the cytochrome P450 enzyme debrisoquine/spartein hydroxylase. Forty-five patients meeting the DSM IV criteria for schizophrenia, chronic course, were recruited. The patients were examined for the mutations CYP2D6*3, CYP2D6*4 and CYP2D6*5. The CYP2D6 genotype distribution in the patient group did not differ from that in healthy Caucasian populations. Tardive dyskinesia was found in 26 patients (57.8%). When comparing patients without CYP2D6 mutations with patients heterozygous for one mutation, we found a higher incidence of TD in the latter (81.3% vs. 46.4%, p = 0.031, multiple regression analysis), which demonstrates a significant influence of the CYP2D6 genotype of the manifestation of TD. As slight differences in the metabolism of drugs in patients heterozygous for CYP2D6 mutations and patients without such mutations are known, we conclude that heterozygous carriers of 2D6 mutated alleles may show an increased susceptibility to developing TD.

Receptor and Transporter Imaging Studies in Schizophrenia, Depression, Bulimia and Tourette's Disorder—Implications for Psychopharmacology-

Summary: Considerable progress has been achieved over the past 15 years in uncovering the biological basis of major psychiatric disorders. To determine patterns of brain dysfunction and to uncover the mechanism of action of centrally active compounds we used single photon emission computerized tomography (SPECT) as well as positron emission tomography (PET) in patients diagnosed with schizophrenia, depression, bulimia and Tourettes disorder. Striatal D2 and 5-HTIA receptors were studied in schizophrenia and 5-HT transporters (5-HTT) in depression and bulimia. Patients were either drug-naive or drug free, or we studied the influence of specifically acting compounds on receptor/transporter occupancy. We could demonstrate that atypical antipsychotics have a dose-dependent (with the exception of clozapine and quetiapine) lower striatal D2 receptor occupancy rate compared with typical neuroleptics, paralleling the more favourable extrapyramidal side effects of atypical antipsychotics. However, no association between striatal D2 receptor occupancy rates and antipsychotic efficacy has been found. The measurement of S-HTIA receptors in drug-naïve schizophrenic patients using the in vivo PET methodology revealed an increase of cortical 5-HTIA receptor binding potential in schizophrenia. β-CIT as a ligand for measurement of 5-HT transporter densities (5-HTT) revealed lower rates in depression compared to age-and sex-matching healthy controls, a measurement that has also been obtained for bulimia. We also documented seasonal variations in brain serotonergic function by our finding of reduced brain 5-HTT availability in winter (compared to summer) in healthy controls. Furthermore, displaceable [124I]/β-CIT binding in the area corresponding to the left striatum (representing predominantly the density of dopamine transporters) was significantly reduced in SAD patients compared to healthy controls. In depression as well as in bulimia, selective serotonin reuptake inhibitors significantly decreased the β-CIT binding potential, however, no significant dose relationship has been obtained in depression. Genotyping depressed patients for the serotonin transporter promoter gene region (5-HTTLPR) did not provide evidence for in vivo functional regulation of 5-HTT availability by 5-HTTLPR in the thalamus-hypothalamus and mesencephalon-pons of healthy subjects. In patients suffering from Tourettes disorder (TD) we were unable to detect differences of dopamine transporter densities between psychotropic drug-naïve TD patients and controls. Furthermore, no difference could be found between currently treated (with antipsychotics) and psychotropic drugnaive TD patients. Our data provide insight into the pathophysiology of neuropsychiatric disorders and may guide future psychopharmacological drug developments.

In vivo 123I IBZM SPECT imaging of striatal dopamine-2 receptor occupancy in schizophrenic patients treated with olanzapine in comparison to clozapine and haloperidol

Abstract We investigated the degree of striatal dopamine-2 (D2) receptor occupancy in six schizophrenic patients receiving clinically effective antipsychotic treatment with olanzapine 10–25 mg/day in comparison to patients treated with clozapine 300–600 mg/day (n = 6) or haloperidol 5–20 mg/day (n = 10). 123I Iodobenzamide (IBZM) and single photon emission computerized tomography (SPECT) were used for the visualization of striatal D2 receptors. For the quantification of striatal D2 receptor occupancy, striatal IBZM binding in patients treated with antipsychotics was compared to that in untreated healthy controls (n = 8) reported earlier. Olanzapine led to a mean striatal D2 receptor occupancy rate of 75% (range 63–85). Haloperidol-treated patients showed dose-dependently (Pearson r = 0.64; P < 0.05) a significantly higher (P < 0.05) mean occupancy rate of 84% (range 67–94). During clozapine treatment, the mean D2 receptor occupancy of 33% (range < 20–49) was significantly lower than with olanzapine (P < 0.005). The higher striatal D2 receptor occupancy of haloperidol was correlated with the incidence and severity of extrapyramidal motor side-effects (EPS). No clinical relevant EPS occurred during treatment with olanzapine or clozapine. There was no correlation between the degree of striatal D2 receptor occupancy and clinical improvement.

The citalopram challenge test in patients with major depression and in healthy controls

Neuroendocrine challenge tests in depressed patients have revealed a blunted hormonal reaction to serotonergic stimuli. In the present study, citalopram was chosen as the serotonergic agent for neuroendocrine stimulation. Compared to earlier challenge agents, citalopram has the advantage of serotonergic selectivity, its application is well tolerated and the possibility of intravenous application reduces pharmacokinetic interference. Sixteen patients suffering from an acute episode of major depression and 16 healthy controls underwent the stimulation procedure with 20 mg of citalopram and placebo. Whereas significant differences in the secretion of prolactin and cortisol between citalopram and placebo challenge were observed in the control group, no differences were found in the group of depressed patients. Comparison of depressed patients and controls showed a significantly blunted prolactin secretion in patients. Differences in cortisol secretion following serotonergic stimulation with citalopram did not become significant. The stimulation procedure was well tolerated in all subjects, although a higher number of side effects was observed in the control group. The amount of side effects did not correlate with the hormone responses. These results are in line with the hypothesis of serotonergic hypofunction in depressed patients. In conclusion, the 20-mg citalopram challenge test is thought to be a promising tool for further investigation of serotonergic function in psychiatric illness.

Dopamine- and serotonin-receptors in schizophrenia: results of imaging-studies and implications for pharmacotherapy in schizophrenia.

Abstract Considerable progress has been achieved over the past 15 years in uncovering the biological basis of major psychiatric disorders. Since psychopharmacological treatment is thought to act on the underlying biological basis of the disease, brain imaging techniques enable us to understand the mechanism of action of such compounds. Positron emission tomography (PET) as well as single photon emission computerized tomography (SPECT) are important tools used to determine patterns of brain dysfunction and to uncover the mechanism of action for antipsychotic compounds. These techniques allow us to determine striatal D2 receptor as well as cortical 5-HT2A receptor occupancy rates which are linked, at least partly, to clinical efficacy as well as side effect rates. In general it has been shown that atypical antipsychotics have a lower striatal D2 receptor occupancy rate than typical antipsychotics, parallelling the more favorable extrapyramidal side effects of atypical antipsychotics, and as a group effect they have a high 5-HT2A occupancy compared to low rates for typical agents. However, there is no association between striatal D2 receptor occupancy rates and antipsychotic efficacy but 5-HT2A occupancy rates are associated with favorable treatment for depressive symptoms within schizophrenia and improvement of cognitive function. The availability of ligands for measurement of extrastriatal D2 receptors or different 5-HT receptors (e.g. 5-HT1A) will further shed light on the pathophysiology of schizophrenia as well as possible psychopharmacological treatment perspectives.

Sertindole and dopamine D2 receptor occupancy in comparison to risperidone, clozapine and haloperidol – a 123I-IBZM SPECT study

Abstract The striatal D2 dopamine binding was studied in schizophrenic patients treated with the novel atypical antipsychotic drug sertindole (n = 10). Comparisons were obtained with haloperidol (n = 8), clozapine (n = 6), risperidone (n = 11) and untreated healthy controls (n = 8) of a dataset which has partly been reported previously. 123I-Iodobenzamide (IBZM) single photon emission computerized tomography (SPECT) was used for estimation of striatal dopamine D2 receptor binding. Sertindole-treated patients exhibited significantly (P < 0.001) lower levels of striatal D2 binding (BG/FC ratio:1.28) compared with those treated with haloperidol (BG/FC ratio:1.09) and risperidone (8 mg:1.18) but significantly (P < 0.005) higher levels compared with clozapine (BG/FC ratio:1.49). However, if patients were pretreated with a depot neuroleptic, significantly (P < 0.05) higher striatal D2 binding (BG/FC ratio:1.12) has been obtained. Since sertindole has been shown to exert distinct clinical efficacy for treatment of positive and negative symptoms, our data are indicative that antipsychotic efficacy is not associated with a high degree of striatal D2 receptor occupancy in schizophrenic patients.

Quetiapine in the Treatment of Borderline Personality Disorder

Affective dysregulation, impulsivity and cognitiveperceptual difficulties are the psychopathological nuclear dimensions of Borderline Personality Disorder (BPD). Psychopharmacological treatment may become necessary during episodes of acute decompensation in which suicidal or self-destructive behaviour erupts. Some classes of psychotropic drugs have demonstrated efficacy in diminishing symptom severity and optimising functioning, such as antidepressants, mood stabilizers, benzodiazepines, opiate antagonists and antipsychotics. Conventional antipsychotics are the best-studied psychotropic medications for BPD, but nonadherence is often due to their severe side effects. Preliminary data reveal efficacy of atypical antipsychotics in BPD. We describe the impact of the novel antipsychotic drug quetiapine on severe self-mutilation in two female patients with the diagnoses of BPD. In both cases, monotherapeutic treatment with quetiapine was well tolerated and resulted in a marked improvement of impulsive behaviour and, over time, overall level of function. Though promising, our findings have to be regarded as preliminary. Due to the overall paucity of data there is still insufficient evidence to make a strong recommendation concerning continuation and maintenance therapy with atypical antipsychotics in BPD. Thus, there is a clear need for further controlled studies to evaluate pharmacological treatment options for this disorder.

Pramipexole as adjunct to haloperidol in schizophrenia Safety and efficacy

Pramipexole, a presynaptic dopamine D2/D3 autoreceptor agonist, has been given to haloperidol-treated patients with schizophrenia (n = 15) in an effort to ameliorate residual positive and negative symptoms that have not been satisfactorily influenced by haloperidol alone. Total scores of the positive and negative symptom scale (PANSS) decreased by more than 20% in 9 of 15 patients (reduction of total score: 22-62%). Serious adverse events did not occur. Three of the 15 patients dropped out due to worsening of schizophrenia. Insomnia, as the most frequent side effect, occurred in 4 patients. No clinically relevant electrocardiographic and laboratory changes were reported. This study supports the safety of the treatment of schizophrenia with pramipexole and haloperidol as a combination therapy. However, further clinical studies are required to support these preliminary findings.

Clonazepam in the long-term treatment of patients with unipolar depression, bipolar and schizoaffective disorder

Abstract The value of a long-term treatment with clonazepam in the prophylaxis of affective disorder is discussed controversially in the scientific literature. Altogether there are only a few reports on the use of this compound as a mood stabilizer, most of them describing patients suffering from bipolar affective disorder. The aim of this investigation was to evaluate clonazepam as a phase prophylactic medication in affective disorder. We conducted a retrospective chart review in 34 out-patients of our lithium clinic (15 suffering from unipolar depression, 15 from bipolar disorder, four from schizoaffective disorder), who had been treated with clonazepam as a long-term medication. Clonazepam was either given as monotherapy, or as in the case of lithium non-responders, as adjunctive therapy. Patients with unipolar depression had significantly (P=0.026) less depressive episodes after initiation of treatment with clonazepam. Patients with bipolar disorder did not benefit from this therapy. Neither manic/hypomanic phases nor depressive episodes were reduced in this group of patients. Interestingly, clonazepam also reduced affective phases in our four schizoaffective patients on a trend level. Our results indicate that patients with unipolar depression may benefit from a maintenance treatment with clonazepam. Due to methodological limitations our results need to be replicated in controlled double-blind randomized clinical trials.

Efficacy, cardiac safety and tolerability of sertindole: a drug surveillance.

&NA; Sertindole is a novel atypical antipsychotic, which has shown efficacy in the treatment of positive and negative symptoms of schizophrenia in phase II and III studies. Furthermore, these studies have demonstrated tolerability and a favourable side‐effect profile. In contrast to classical antipsychotics, sertindole was not associated with extrapyramidal symptoms (EPS). We report drug surveillance data in 34 comorbid and comedicated sertindole treated patients suffering from different psychotic disorders. The drug surveillance consisted of two distinct phases: inpatient treatment and outpatient follow‐up. Clinical global impression (severity and improvement of illness), psychotic symptoms, side‐effects, and blood parameters have been carefully documented. With special respect to cardiac safety electrocardiograms (ECGs) have been recorded twice (during sertindole treatment and during treatment with an antipsychotic different from sertindole). Recommended ECG‐parameters for assessment of the proarrhythmic risk of a drug have been calculated (QTc‐, QTc2‐interval; QT‐, QTc‐dispersion). The majority of patients (n = 29) have been treated previously with several typical and/or atypical antipsychotics. We observed a clinical response to sertindole treatment in 29 patients (85%). Both positive and negative symptoms improved with sertindole and no severe side‐effects have been documented. EPS occurred at placebo level. A mean QTc‐interval prolongation of 19.7 ms (4.7%) has been detected. None of the patients developed clinical or electrocardiographic evidence of cardiac dysrhythmia during sertindole treatment, or other clinical evidence of cardiac abnormalities. In summary, sertindole did show efficacy for positive and negative symptoms together with a favourable side‐effect profile. No evidence for an increased proarrhythmic risk has been found.