Journal of Psychopharmacology

Sexual dysfunction is a major, although poorly understood, side-effect of treatment with antipsychotic drugs. We have recently show marked disruption of reproductive function and weight gain in female rats treated subchronically with risperidone and haloperidol. The aim of the present study was to examine further the potential relationship between reproductive dysfunction and weight gain in female rats treated with olanzapine. The effects of olanzapine on weight gain, food and water intake, intra-abdominal fat, the oestrous cycle and uterine weight were assessed in group-housed adult female hooded-Lister rats. Olanzapine (0.5-4.0 mg/kg i.p.) or vehicle was administered once daily for 21 days and body weight, food and water intake measured, with histological examination of vaginal lavage to determine the stage of the oestrous cycle. On day 22, animals were sacrificed and intra-abdominal fat, wet and dry uterine weights measured. Olanzapine induced significant weight gain with concomitant increases in food and water intake and intra-abdominal fat without an effect on the oestrous cycle, wet and dry uterine weights or plasma prolactin levels. These results confirm the ability of olanzapine to induce weight gain in female rats on unrestricted normal diet with a concomitant increase in food and water intake and increased intra-abdominal fat. These effects of olanzapine were produced in the absence of any apparent impairment in reproductive function, in contrast to the substantial disruption of oestrous and uterine atrophy previously shown in rats treated with risperidone and haloperidol.

In view of the evidence that cognitive deficits in schizophrenia are critically important for long-term outcome, it is essential to establish the effects that the various antipsychotic compounds have on cognition, particularly second-generation drugs. This parallel group, placebo-controlled study aimed to compare the effects in healthy volunteers (n = 128) of acute doses of the atypical antipsychotics amisulpride (300 mg) and risperidone (3 mg) to those of chlorpromazine (100 mg) on tests thought relevant to the schizophrenic process: auditory and visual latent inhibition, prepulse inhibition of the acoustic startle response, executive function and eye movements. The drugs tested were not found to affect auditory latent inhibition, prepulse inhibition or executive functioning as measured by the Cambridge Neuropsychological Test Battery and the FAS test of verbal fluency. However, risperidone disrupted and amisulpride showed a trend to disrupt visual latent inhibition. Although amisulpride did not affect eye movements, both risperidone and chlorpromazine decreased peak saccadic velocity and increased antisaccade error rates, which, in the risperidone group, correlated with drug-induced akathisia. It was concluded that single doses of these drugs appear to have little effect on cognition, but may affect eye movement parameters in accordance with the amount of sedation and akathisia they produce. The effect risperidone had on latent inhibition is likely to relate to its serotonergic properties. Furthermore, as the trend for disrupted visual latent inhibition following amisulpride was similar in nature to that which would be expected with amphetamine, it was concluded that its behaviour in this model is consistent with its preferential presynaptic dopamine antagonistic activity in low dose and its efficacy in the negative symptoms of schizophrenia.

Contraction of the orbicularis oculi muscle in response to a sudden loud sound (acoustic startle response) and the N1/P2 component of the auditory evoked potential are both attenuated when a brief low-intensity stimulus is presented 30-500 ms before the ‘startle-eliciting’ stimulus (PPI). Here, we report the effects of the ‘atypical’ antipsychotic drug quetiapine and the ‘conventional’ antipsychotic haloperidol on these responses. Sixteen males (aged 19-38 years) participated in four sessions at 7-day intervals, in which they received quetiapine 12.5 mg, quetiapine 25 mg, haloperidol 3 mg and placebo, according to a balanced double-blind design. Electromyographic (EMG) responses of the orbicularis oculi muscle and N1/P2 auditory evoked potentials were recorded in a 20-min session, 2 h after treatment. Subjects received 40 trials in which 1-kHz sounds were presented: (i) 40 ms, 115 dB (‘pulse alone’ trials) and (ii) 40 ms, 85 dB, followed after 120 ms by 40 ms, 115 dB (‘prepulse/pulse’ trials). Mean amplitudes of the EMG response and the N1/P2 potential were derived from the pulse-alone trials and, in each case, percentage PPI was calculated. Serum prolactin was measured after each treatment, and autonomic (heart rate, blood pressure, salivation) and psychological (visual analogue self-ratings of mood and alertness, critical flicker fusion frequency) measures were taken before and after each treatment. Quetiapine 12.5 mg and 25 mg significantly reduced the amplitude of the EMG response without altering its inhibition by prepulses; haloperidol had no effect on EMG response amplitude or PPI. Neither drug affected N1/P2 amplitude or PPI of this response. Quetiapine, but not haloperidol, reduced subjective alertness and critical flicker fusion frequency. Haloperidol, but not quetiapine, elevated serum prolactin level. The ability of quetiapine to attenuate the startle response may reflect its sedative action.

Deficits in sensorimotor gating or prepulse inhibition (PPI) have been demonstrated repeatedly in patients with schizophrenia or with schizotypal personality disorder, but not consistently in schizotypal non-psychiatric controls. The appearance of normal PPI in this group has been interpreted as reflecting a discontinuous underlying vulnerability to psychosis in high-risk groups. An alternative interpretation is that underlying vulnerability to psychosis is continuously distributed in the normal population (Claridge, 1972, 1987), and therefore that performance on information processing tasks should vary continuously with increasing levels of schizotypy in non-clinical populations. We attempted to examine further the notion of a continuous relationship between PPI and schizotypy in 44 (17 female, 27 male) healthy, non-smoking subjects controlling for menstrual phase. In this selected sample, the findings do not support a continuum model, and suggest that PPI deficits may indeed be the result of a discontinuous neurophysiological change in those with psychotic illness, rather than one continuously distributed in the normal population.

The role of certain drug metabolizing enzymes in cardiotoxicity, such as CYP2D6 for thioridazine, has been suggested. Risperidone has been shown to inhibit the delayed rectifier leading to lengthening of cardiac repolarization. The heart-rate corrected QT (QTc) interval lengthening has been reported in psychiatric patients receiving risperidone under steady-state conditions. CYP2D6 is involved in the metabolism of risperidone to 9-hydroxy (OH)-risperidone. CYP2C9 enzyme is also involved in the metabolism of several psychotropic drugs, although there are no data about its implication in risperidone metabolism. The present study aimed to evaluate the influence of CYP2D6 and CYP2C9 genotypes, and plasma concentrations of risperidone and 9-OH-risperidone on the QTc interval in patients under steady-state conditions. The relevance of CYP2D6 and CYP2C9 genotypes on risperidone metabolism was also analysed. Thirty-five White European psychiatric patients receiving risperidone monotherapy were studied. QTc interval was longer (p < 0.05) in subjects with one active CYP2D6 gene compared to those with two. The number of CYP2D6 active genes was related to the dose-corrected plasma concentration of risperidone (p < 0.05), the active moiety (risperidone plus 9-OH-risperidone) (p < 0.05) and the risperidone/9-OH-risperidone ratio (p < 0.05). CYP2C9genotypes were not related to plasma concentrations of risperidone or 9-OH-risperidone, nor QTc interval. The results suggest that CYP2D6, but not CYP2C9, may be related to QTc lengthening during treatment with risperidone. The effect of the CYP2D6 genotype in risperidone metabolism is also shown.

Previous studies suggest a modulatory role of serotonin (5-HT) in experimentally-induced panic attacks. In the current study, we investigated the acute effects of 5-HT precursor l-5-hydroxytryptophan (5-HTP) on the response to panicogenic challenge with cholecystokinin-tetrapeptide (CCK-4) in healthy volunteers. Thirty-two subjects were randomized to receive either 200 mg of 5-HTP or placebo with the CCK-4 challenge following in 90 min in a double-blind, parallel-group design. The results showed a nonsignificant difference between the groups in panic rate (19% after 5-HTP and 44% after placebo, p = 0.13) with a trend for lower intensity of symptoms after 5-HTP (p = 0.08). Further analysis by gender revealed that females in the 5-HTP group had a significantly lower panic rate and intensity of cognitive symptoms whereas, in males, the effect of 5-HTP was limited to lowering the intensity of somatic panic symptoms. Thus, an increased availability of 5-HT may have a gender-dependent protective effect in CCK-4-induced panic.

High doses of antidepressants are often used for treatment-resistant depression. Venlafaxine, a dual serotonin and noradrenaline reuptake inhibitor, has been shown to have a tolerable side-effect profile in previous studies using doses of up to 375 mg/day. We investigated the tolerability of higher than currently recommended doses of venlafaxine using the UKU side-effect rating scale. Seventy outpatients fulfilling DSM-IV criteria for major depressive disorder were recruited into two demographically matched groups according to their daily dosage of venlafaxine: high dose n = 35 (≥ 375 mg/day, range 375-600 mg, average 437 mg/day) or standard dose n = 35 (< 375 mg/day, range 75-300 mg, average 195 mg/day. Clinical characteristics were noted and the UKU side-effect rating scale was administered to a subsample of patients. The most frequently reported complaints in both groups were increased fatigue (48%), concentration difficulties (48%), sleepiness/sedation (37%), failing memory (44.4%) and weight gain (29.6%). Apart from weight gain, the complaints were found to be experienced significantly more severely by the high-dose group. Six patients discontinued venlafaxine due to intolerable side-effects but only two of these patients were on a high dose. There was a tendency for mildly raised blood pressure in 10% of patients on an average dose of 342 mg/day. However, no difference between the two groups was found. This preliminary open study demonstrates that venlafaxine is tolerated at higher than British National Formulary recommended doses (i.e. up to 600 mg daily). However, increased frequency and severity of reported side-effects in the high-dose group are not associated with increased rates of discontinuation.

To investigate the efficacy and cognitive and psychomotor effects of venlafaxine and dothiepin in elderly patients with moderate major depression. A prospective, randomized, double-blind, parallel-group, active comparator controlled study was conducted. Eighty-eight patients (aged ≥ 60 years) were enrolled. Each patient received either venlafaxine (immediate release formulation) 37.5 mg twice per day or dothiepin 25 mg mane followed by 50 mg nocte for 26 weeks. Efficacy was assessed with the Montgomery-Asberg Depression Rating Scale and the Hamilton Depression Rating Scale. A psychometric test battery to assess cognitive function, activities of daily living and sleep consisted of Critical Flicker Fusion (CFF), Short-term Memory - Kim’s Game, Cognitive Failures Questionnaire, Milford Epworth Sleepiness Scale, Leeds Sleep Evaluation Questionnaire, and an Accident Scoring Questionnaire. Quality of Life Questionnaires (Short Form 36 and Quality of Life in Depression Scale) were also administered. Venlafaxine significantly (p < 0.05) raised CFF scores compared to baseline but had no effect on any other measure. Dothiepin significantly (p < 0.05) lowered CFF threshold, and increased ratings of both sedation and difficulty in waking. The results showed that venlafaxine at doses of 37.5 mg b.i.d. in elderly depressed patients is free from disruptive effects on cognitive function and psychomotor performance.

Loss of noradrenergic (NE) neurones in the locus ceruleus and compensatory changes in NE activity have been described in Alzheimer’s disease (AD), but have never been linked to treatment. The hypothesis of this study was that central NE responsivity would predict aggression response to treatment with a NE medication, pindolol. Fifteen institutionalized AD subjects [Mini-Mental State Examination (MMSE), mean 3.3 ± 4.6] with significant behavioural disturbances (Neuropsychiatric Inventory Score, mean 30.6 ± 14.6) were studied. Growth hormone (GH) response to clonidine challenge (5 μg/kg) was used as a measure of central NE responsivity. Subjects were then randomized to 7 weeks of treatment with pindolol, maximum dose 20 mg b.i.d., or an identical placebo capsule in a cross-over design. The primary outcome measure was change on the retrospective Overt Aggression Scale (r-OAS). Five of 11 completers (45%) had decreased total r-OAS scores. There was significant improvement noted on the r-OAS verbal aggression subscale (paired t = -2.5, p = 0.03) compared to placebo, but not r-OAS total. Higher baseline aggression, higher MMSE and lower GH response predicted improvement in aggression, accounting for 82% of the variance (r = 0.91, F = 10.5, p = 0.006). Changes in NE responsivity, as reflected by a blunted GH response to clonidine challenge and more severe aggression, were associated with better response to the NE agent pindolol. Individual patient characteristics, including underlying neurotransmitter changes, may be useful for predicting response to therapy.

Previous single-dose studies have shown clear blood pressure-lowering effects of a potential sustained release (SR) profile of rilmenidine, with concentration-dependent effects on the central nervous system. The aim of this study was to evaluate potential changes in concentration-effect-relationships for these central nervous system effects during a 4-week treatment period with an experimental SR formulation of rilmenidine 3 mg once daily in 15 mild-to-moderate hypertensive patients. The central nervous system effects of the treatment were evaluated using saccadic eye movements for sedative effects and visual analogue scales for subjective effects on alertness, mood and calmness. Measurements for pharmacokinetic and pharmacodynamic evaluations were performed on the first day of the treatment period and repeated after 1 week and 4 weeks of treatment. Drug concentrations increased during the study, whereas treatment related reductions in saccadic peak velocity (SPV) remained similar on all three study days. The slopes of the concentration-effect-curves for SPV remained unchanged throughout the study, while the intercepts tended to increase as a result of increased pre-dose values. Similar effects were observed for visual analogue scales for alertness: pre-dose values increased significantly during the study, while the size of the treatment responses (slopes) remained unaltered. The reasons for these adaptations cannot be determined but may include drug tolerance and habituations to study procedures. Blood pressure control remained stable and adequate throughout the study.

This study aimed to examine patterns of illicit recreational drug use, alcohol consumption, and smoking in a community-based population sample. A postal questionnaire survey was conducted of people who were selected at random from the Electoral registers of Cardiff and Merthyr Tydfil. Twelve percent of respondents reported illicit recreational drug use in the last year, and 7% in the last month. Among respondents aged under 25 years, 34% (39% of males and 31% of females) had used illicit drugs in the last year, and 19% (23% of males and 17% of females) in the last month. Twenty-one percent of respondents smoked (20% of males and 22% of females). Twenty-seven percent of respondents reported drinking more alcohol than currently recommended sensible limits (36% of males and 21% of females). Among respondents aged under 25 years, 53% of men and 38% of women drank over these limits. Illicit drug use was associated with heavy alcohol consumption and, in particular, with smoking. Smoking and heavy alcohol consumption combined was most strongly associated with illicit drug use. Rates of illicit recreational drug use were higher than have previously been reported for Wales. Illicit drug use and smoking varied with age, sex, work status and geographical location, whereas heavy alcohol consumption varied with age, sex and work status, but not geographical location. Both smoking and alcohol consumption were associated with illicit drug use, with smokers who were also heavy drinkers being those most likely to report illicit drug use.

This study aimed to examine demographic, lifestyle, mental health and personality factors associated with illicit recreational drug use, heavy alcohol consumption and smoking in a community-based population sample. A postal questionnaire survey was conducted of people who were selected at random from the Electoral registers of Cardiff and Merthyr Tydfil. Illicit drug use was associated with risk taking, neuroticism, being male, having a higher education qualification, not being married, being unemployed, being aged under 25 years, smoking, heavy alcohol consumption and living in Cardiff. Smoking was associated with anxiety, depression, being female, lower income and educational qualifications, looking after the family or home, being aged over 25 years, illicit drug use and heavy alcohol use. Heavy alcohol consumption was associated with not being depressed, experiencing sleeping problems, risk taking, being male, higher income, no higher educational qualification, not being married, being a student, being aged under 25 years, smoking and illicit drug use. Illicit drug use, smoking and heavy alcohol use were strongly associated with each other. Illicit drug use was associated with alcohol use and, to an even greater extent, with smoking. Illicit drug and alcohol use were associated with similar characteristics, but smoking was associated with a rather different demographic combination.

The objective of this review was to determine the effectiveness, adverse effects and acceptability of folate in the treatment of depression. Electronic databases (Cochrane Controlled Trials Register and the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register) and reference lists were searched, and authors, experts and pharmaceutical companies contacted to identify randomized controlled trials that compared treatment with folic acid or 5 ′-methyltetrahydrofolic acid to an alternative treatment, for patients with a diagnosis of depressive disorder. Three randomized trials (247 participants) were included. Two studies assessed the use of folate in addition to other treatment, and found that adding folate reduced Hamilton Depression Rating Scale (HDRS) scores on average by a further 2.65 points [95% confidence interval (CI) 0.38-4.93]. Fewer patients treated with folate experienced a reduction in their HDRS score of less than 50% at 10 weeks (relative risk 0.47, 95% CI 0.24-0.92). The remaining study found no statistically significant difference when folate alone was compared with trazodone. The identified trials did not find evidence of any problems with the acceptability or safety of folate. The limited available evidence suggests folate may have a potential role as a supplement to other treatment for depression. It is currently unclear if this is the case both for people with normal folate levels, and for those with folate deficiency.

Transcranial magnetic stimulation (TMS) provides new possibilities for studying localized changes in the electrical properties of the human cortex. TMS combined with electromyography (EMG) has revealed that drugs blocking Na⁺ or Ca²⁺ channels such as phenytoin, lamotrigin or carbamazepine change the motor threshold without affecting intracortical inhibition or facilitation. Gabaergic agents vigabatrin, lorazepam, diazepam, baclofen and ethanol do not affect the motor threshold, but increase intracortical inhibition and decrease facilitation. N-methyl-D-aspartate receptor antagonists riluzole, dextromethorphan and memantine have similar effects. Dopamine receptor antagonists such as haloperidol, but not sulpiride, decrease intracortical inhibition and increase intracortical facilitation. Other monoamines, such as serotonin and noradrenaline, may have some modulating effect on the cortical excitability. However, TMS combined with EMG gives only indirect evidence about the excitability of the motor cortex because spinal mechanisms may contribute to the results. Cortical excitability can be studied directly by combining TMS with brain imaging methods such as electroencephalography (EEG). Motor and non-motor areas can be stimulated and subsequent brain activity can be measured. Ethanol has been shown to modulate EEG responses evoked by motor-cortex TMS, the effects being largest at the right prefrontal cortex, meaning that ethanol would have changed the functional connectivity. Furthermore, alcohol decreases amplitudes of EEG responses after the left prefrontal stimulation mainly in anterior parts of the cortex, which may be associated with the decrease of the prefrontal cortical excitability. Taken together, TMS provides a new insight to the actions of central nervous system drugs at the cortical level.

There is a worldwide increasing use of herbs which are often administered in combination with therapeutic drugs, raising the potential for herb-drug interactions. St John’s wort (Hypericum perforatum) is one of the most commonly used herbal antidepressants. A literature search was performed using Medline (via Pubmed), Biological Abstracts, Cochrane Library, AMED, PsycINFO and Embase (all from their inception to September 2003) to identify known drug interaction with St John’s wort. The available data indicate that St John’s wort is a potent inducer of CYP 3A4 and P-glycoprotein (PgP), although it may inhibit or induce other CYPs, depending on the dose, route and duration of administration. Data from human studies and case reports indicate that St John’s wort decreased the blood concentrations of amitriptyline, cyclosporine, digoxin, fexofenadine, indinavir, methadone, midazolam, nevirapine, phenprocoumon, simvastatin, tacrolimus, theophylline and warfarin, whereas it did not alter the pharmacokinetics of carbamazepine, dextromethorphan, mycophenolic acid and pravastatin. St John’s wort decreased the plasma concentration of the active metabolite SN-38 in cancer patients receiving irinotecan treatment. St John’s wort did not alter the pharmacokinetics of tolbutamide, but increased the incidence of hypoglycaemia. Several cases have been reported that St John’s wort decreased cyclosporine blood concentration leading to organ rejection. St John’s wort caused breakthrough bleeding and unplanned pregnancies when used concomitantly with oral contraceptives. It also caused serotonin syndrome when coadministered with selective serotonin-reuptake inhibitors (e.g. sertaline and paroxetine). Both pharmacokinetic and pharmacodynamic components may play a role in these interactions. Because the potential interaction of St John’s wort with other drugs is a major safety concern, additional systematic research on herb-drug interactions and appropriate regulation in herbal safety and efficacy is needed.

Transdermal fentanyl is an opioid analgesic that is effective on chronic pain, and which appears to be advantageous due to several factors such as ease of administration, the relatively stable serum concentration and long dose intervals. Nevertheless, the danger of abuse and dependence exists among patients who are prescribed fentanyl patches. We present a case of transdermal fentanyl abuse, where the administration route of the drug was changed. Our patient, who had no history of substance abuse and who suffered from chronic nonmalignant pain, used the fentanyl transdermal patches as oral transmucosal medication, raising the dose by ten-fold. This abuse of the drug was only for analgesic purposes without seeking anxiolysis and/or euphoria. After treatment and progressive reduction of fentanyl, the patient remains in good condition, and is currently taking the initial dose of the drug transdermally, without having experienced any withdrawal symptoms.

We present a series of three cases who developed manic symptoms on introduction of quetiapine to their medication regime. All were male, with long-standing psychotic illnesses (schizophrenia/schizoaffective disorder), relatively well maintained on medication until their deterioration which prompted a review of their medication. The dose range of prescribed quetiapine was 300-800 mg daily. Two patients had previously received antidepressants without displaying manic symptoms. The mania subsided on withdrawal of quetiapine in two patients. The third patient continued on quetiapine but with the addition of zuclopenthixol depot. Sodium valproate was prescribed to the other two patients, and quetiapine was discontinued. These cases indicate that a side-effect of quetiapine may be mood elevation. An ability to elevate mood while controlling psychoses would be helpful in the treatment of post-psychotic and bipolar depression. Its clinical importance in the control of manic episodes, for which atypical antipsychotics are used increasingly, is uncertain.