Human pharmacology of current and new treatments for schizophrenia

The studies in this thesis together show different ways of studying human pharmacology, give an impression of the current drug development in schizophrenia, and provide examples how human pharmacology can be applied in an early stage of drug development in healthy volunteers. The investigated compounds show that the main pharmacological focus in this area has shifted from psychosis to improvement of individual negative or cognitive symptom complexes, from direct receptor inhibition to indirect receptor modulation, and from single drug strategies to combination therapies, each targeted at different symptoms. We have tried to create a pharmacological fingerprint of the investigated compounds by making use of an intensive CNS test battery to measure effects in different functional domains of the brain and additional 'tools' (i.e. positive controls, dose escalation, PK-PD modeling and pharmacological challenge tests) to improve the reliability of the tests. This diversity of drug development strategies and range of neurotransmitters in schizophrenia reflects the increasing complexity of neuropharmacological hypotheses in this field. Despite these difficulties, incremental changes in drug characteristics and treatment strategies may well lead to the introduction of new classes or combinations of drugs in the future.The publication of this thesis was financially supported by the foundation Centre for Human Drug Research (CHDR), Leiden, the NetherlandsUBL - phd migration 201

Does olanzapine inhibit the psychomimetic effects of Delta(9)-tetrahydrocannabinol?

Stress-related psychiatric disorders across the life spa

Central nervous system effects of the interaction between risperidone (single dose) and the 5-HT6 antagonist SB742457 (repeated doses) in healthy men

UNLABELLED WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Several lines of evidence suggest a possible role of 5-HT(6) receptor antagonists in dementia or cognitive dysfunction of schizophrenia. SB-742457 is a potent 5-HT(6) antagonist and has shown efficacy in different animal models of cognitive impairment. It is currently in development as a cognitive enhancer. Risperidone, commonly used to control agitation and psychotic features in both schizophrenia and Alzheimer's disease, is a D(2)/5-HT(2A ) antagonist with low affinity for 5-HT(6) receptors and limited effects on cognitive parameters. WHAT THIS STUDY ADDS • As the combination of risperidone and SB-742457 may constitute a reasonable combination in cognitively impaired patients, pharmacodynamic interaction effects were investigated in this study. The only significant drug-drug interaction was a small increase of electroencephalogram (EEG) alpha and beta bands, which might suggest mild arousing activity of SB-742457 on the central nervous system-depressant effects of risperidone. The clinical relevance of these findings in patients remains to be established. Additionally, this study provided an extensive multidimensional pharmacodynamic profile of risperidone in healthy volunteers, showing that this antipsychotic suppresses motor performance (eye-hand coordination, finger tapping and postural stability), alertness, memory and neurophysiological functions (saccadic eye movements and EEG power spectrum). AIM Several lines of evidence suggest a possible role of 5-HT(6 ) receptor antagonists in cognitive dysfunction of schizophrenia. Atypical antipsychotics, such as risperidone, are currently used in these disorders. Therefore, the pharmacological interactions between the 5-HT(6) antagonist SB-742457 and risperidone were investigated in the light of possible co-medication. METHODS A randomized, double-blind, two-way crossover design was used to study the interaction between multiple doses SB-742457 50 mg and a single dose risperidone 2 mg in 18 healthy subjects. RESULTS Treatment was well tolerated. The most common adverse event was somnolence in 83% during the combination vs. 50% of subjects after risperidone, 32% after placebo and 11% after SB-742457. Combination treatment produced a statistically significant increase in the maximum plasma concentration of risperidone and had no effect on SB-742457 pharmacokinetics. Risperidone decreased saccadic peak velocity, finger tapping, adaptive tracking, subjective alertness, delayed word recognition and body sway and increased electroencephalogram (EEG) theta power and prolactin. The only pharmacodynamic interaction of risperidone and SB-742457 was an increase of absolute EEG alpha (ratio = 1.25, 95% CI = 1.11, 1.40, P= 0.0004) and beta power (ratio = 1.14, 95% CI = 1.03, 1.27, P= 0.016). No significant effects of SB-742457 alone were found. CONCLUSION The pharmacokinetic interactions between SB-742457 and risperidone detected in this study were not clinically relevant. The increase in EEG alpha and beta power is incompatible with enhanced risperidone activity, but could point to mild arousing effects of the combination. Most pharmacodynamic changes of risperidone are consistent with previously reported data. The potential cognitive effects of SB-742457 remain to be established.Stress-related psychiatric disorders across the life spa

Psychomotor and cognitive effects of a single oral dose of talnetant (SB223412) in healthy volunteers compared with placebo or haloperidol

Central Nervous System (CNS) effects of talnetant, an NK-3 antagonist in development for schizophrenia, were compared to those of haloperidol and placebo. The study was randomised, double-blind, three-way crossover of talnetant 200 mg, haloperidol 3 mg or placebo. Twelve healthy males participated and EEG, saccadic and smooth pursuit eye movements, adaptive tracking, body sway, finger tapping, hormones, visual analogue scales (VAS) for alertness, mood and calmness and psychedelic effects, left/right distraction task, Tower of London and Visual and Verbal Learning Task were assessed. Haloperidol showed (difference to placebo; 95% CI; p-value) decreases in EEG alpha power (-0.87microV; -1.51/-0.22; p = 0.0110), saccadic inaccuracy (2.0%; 0.5/3.6; p = 0.0133), smooth pursuit eye movements (-7.5%; -12.0/-3.0; p = 0.0026), adaptive tracking (-3.5%; -5.4/-1.7; p = 0.0009), alertness (-6.8 mm; -11.1/-2.4; p = 0.0039), negative mood (-4.6 mm; -8.6/-0.6; p = 0.0266), the ability to control thoughts (1.2 mm; 0.2/2.3; p = 0.0214), and an increase of serum prolactin (ratio 4.1; 3.0/5.6; p < 0.0001). Talnetant showed decreased alpha power (-0.69 muV; -1.34/-0.04; p = 0.0390), improved adaptive tracking (1.9%; 0.1/3.7; p = 0.0370) and reduced calmness on VAS Bond and Lader (-4.5 mm; -8.0/-1.0; p = 0.0151). Haloperidol effects were predominantly CNS-depressant, while those of talnetant were slightly stimulatory. The results suggest that talnetant penetrates the brain, but it remains to be established whether this dose is sufficient and whether the observed effect profile is class-specific for NK3-antagonists.Stress-related psychiatric disorders across the life spa

Central nervous system effects of haloperidol on THC in healthy male volunteers

In this study, the hypothesis that haloperidol would lead to an amelioration of Δ9-tetrahydrocannabinol (THC)-induced 'psychotomimetic' effects was investigated. In a double-blind, placebo-controlled, partial three-way crossover ascending dose study the effects of THC, haloperidol and their combination were investigated in 35 healthy, male mild cannabis users, measuring Positive and Negative Syndrome Scale, Visual Analogue Scales for alertness, mood, calmness and psychedelic effects, saccadic and smooth pursuit eye measurements, electroencephalography, Body Sway, Stroop test, Visual and Verbal Learning Task, hormone levels and pharmacokinetics. Compared with placebo, THC significantly decreased smooth pursuit, Visual Analogue Scales alertness, Stroop test performance, immediate and delayed word recall and prolactin concentrations, and significantly increased positive and general Positive and Negative Syndrome Scale score, Visual Analogue Scales feeling high, Body Sway and electroencephalography alpha. Haloperidol reversed the THC-induced positive Positive and Negative Syndrome Scale increase to levels observed with haloperidol alone, but not THC-induced 'high' feelings. Compared with placebo, haloperidol significantly decreased saccadic peak velocity, smooth pursuit, Visual Analogue Scales mood and immediate and delayed word recall and significantly increased Body Sway, electroencephalography theta and prolactin levels. THC-induced increases in positive Positive and Negative Syndrome Scale but not in Visual Analogue Scales feeling high were reversed by haloperidol. This indicates that psychotic-like effects induced by THC are mediated by dopaminergic systems, but that other systems are involved in 'feeling high'. Additionally, the clear reductions of psychotic-like symptoms by a clinically relevant dose of haloperidol suggest that THC administration may be a useful pharmacological cannabinoid model for psychotic effects in healthy volunteers

Early stage development of the glycine-1 re-uptake inhibitor SCH 900435: central nervous system effects compared with placebo in healthy men

Stress-related psychiatric disorders across the life spa

Developing dialogue between a school subject department head and a university education researcher: convergences and divergences in experiencing educational change and complexity

This chapter explores some of the challenges and opportunities in enhancing teacher–researcher relationships by analysing the work activities and environments of the authors, one a former secondary school teacher and subject department head and the other a university education researcher, both working in Queensland, Australia. More specifically, the chapter analyses selections from a lengthy audiorecorded interview between the authors focused on the first-named author’s strategies for engaging with educational change in a complex school environment. The findings of this analysis highlight the mutual benefits of educators and education researchers engaging in this kind of collaboration. More broadly, such a collaboration can help to illuminate some of the wider convergences and divergences that emerge from educational change and complexity in schools and universities alike