Political consumer behaviour among university students in Brazil and Germany: The role of contextual features and core political values.

This study investigates the relationship between political consumerism and core political values (CPVs) among university students in Brazil (N = 414) and Germany (N = 222). Despite the prerequisite to endorse values that are compatible with political consumerism, contextual features of one's immediate environment might affect overall levels of political consumerism. Our results show that political consumerism is significantly associated with higher income in Brazil (but not in Germany). After controlling for income, political consumerism was practised more frequently in Germany than in Brazil, in urban compared with rural areas, and was not dependent on gender. The urban-rural split was stronger in Brazil than in Germany. These results confirm our hypothesis that contextual features are associated with political consumerism. Furthermore, the political value Equality positively predicted political consumerism in both countries. In contrast, Traditional Morality and support of Free Enterprise negatively predicted political consumerism, although the effect sizes of these relationships were only small. These results suggest that political consumerism among university students is widespread in Germany but not in Brazil. Interestingly, regardless of its low prevalence in Brazil, political consumerism is positively associated with the CPV of Equality among university students in both countries.

Habituation of the startle reflex depends on attention in cannabis users.

BACKGROUND: Cannabis use is associated with an attention-dependent deficit in prepulse inhibition of the startle reflex (PPI). The aim of the current study was to investigate startle habituation in cannabis users and healthy controls during two attentional tasks. METHODS: Auditory startle reflex was recorded from orbicularis oculi muscle while participants (12 controls and 16 regular cannabis users) were either attending to or ignoring 100 dB startling pulses. Startle habituation was measured as the absolute reduction in startle magnitude on block 2 (last nine trials) vs. block 1 (first nine trials). RESULTS: Startle habituation with moderate effect sizes was observed in controls and cannabis users only while they were ignoring the startling pulses but not while they were attending to them. Similar results were also observed in controls (lifetime non-users of cannabis) and cannabis users with lifetime cannabis use disorders (CUD). CONCLUSION: Startle habituation appears to depend on selective attention but not on cannabis use. Startle habituation was present when attention was directed away from auditory startling pulses in healthy controls and cannabis users. Such a similar pattern of results in both groups suggests that at least a trend exists towards presence of startle habituation regardless of cannabis use or CUD in otherwise healthy members of the general population.

Cognitive correlates of repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant depression--a pilot study.

BACKGROUND: The aim of the current study was to investigate the cognitive correlates of repetitive transcranial magnetic stimulation (rTMS) in 10 treatment-resistant depression patients. METHODS: Patients received forty 20-min sessions of fast-frequency (10 Hz) rTMS of the left dorsolateral prefrontal cortex (DLPFC) over 20 days. Concept-shift ability (accuracy and duration of performance) was assessed daily with a Modified Concept-Shifting Task (mCST) in patients and in eight healthy volunteers. General cognitive functioning test (Repeatable Battery for the Assessment of Neuropsychological Status; RBANS), Beck Depression Inventory (BDI) and Hamilton Depression Rating Scale (HAM-D) were applied before the first and after the last rTMS. RESULTS: Compared to before rTMS on the first 10 days, the patients performed the mCST significantly more accurately after rTMS on the last 10 days (p < .001, partial eta squared=.78) while the same comparison in healthy volunteers was not statistically significant (p = .256, partial eta squared=.18). A significant improvement in immediate memory on RBANS and reduction in BDI and HAM-D scores were also observed after the last compared to before the first rTMS. CONCLUSION: The rTMS is associated with an improvement in selective cognitive functions that is not explained by practice effects on tasks administered repeatedly. TRIAL REGISTRATION: Name: "Repetitive Transcranial Magnetic Stimulation (rTMS) in the treatment of depression, assessed with HAM-D over a four week period."URL: www.actr.org.au REGISTRATION NUMBER: ACTRN012605000145606.

Practice effects on the modified concept shifting task (mCST): a convenient assessment for treatment effects on prefrontal cognitive function.

BACKGROUND: Trail-making tests, such as the Concept Shifting Task (CST), can be used to test the effects of treatment on cognitive performance over time in various neuropsychological disorders. However, cognitive performance in such experimental designs might improve as a result of the practice obtained during repeated testing rather than the treatment itself. The current study investigated if practice affects the accuracy and duration of performance on the repeatedly administered Concept Shifting Task modified to make it resistant to practice (mCST). The mCST was administered to 54 healthy participants twice a day, before and after a short break, for eight days. RESULTS: The ANOVA and meta-analysis showed that there was no improvement in the mCST accuracy on the last vs. the first trial (Hedges' g = .14, p = .221) or within the session (after vs. before the break on all days; g = .01, p = .922). However, the participants performed the task faster on the last vs. the first trial (g = -.75, p < .001) and after vs. before the break on all days (g = -.12, p = .002). CONCLUSIONS: Repeated administration of the mCST does not affect the accuracy of performance on the test. However, practice might contribute to faster performance on the mCST over time and within each session.

Attention-dependent reduction in prepulse inhibition of the startle reflex in cannabis users and schizophrenia patients--a pilot study.

Our previous report [Kedzior, K., Martin-Iverson, M., 2006. Chronic cannabis use is associated with attention-modulated reduction in prepulse inhibition of the startle reflex in healthy humans. J. Psychopharmacol. 20, 471-484.] indicates that chronic cannabis use in healthy humans is associated with deficits in the attentional modulation of prepulse inhibition of the acoustic startle reflex. The aim of the current study was to compare the attentional modulation of prepulse inhibition among healthy controls, otherwise-healthy cannabis users and schizophrenia patients (non-users) utilising the same attentional paradigm. Auditory startle reflex (the eye blink) was recorded from orbicularis oculi muscle while participants were attending to or ignoring 100 dB pulses and 70 dB prepulses separated by 20-200 ms. Cannabis users and schizophrenia patients showed a significant reduction in prepulse inhibition relative to controls while attending to, but not ignoring, auditory stimuli. These results suggest that the reduction in prepulse inhibition observed in cannabis users and in schizophrenia patients appears to be related to attentional dysfunction.

Validity and consistency of self-reports regarding substance use in general research volunteers, including regular cannabis users and schizophrenia patients.

This study investigated the validity of self-reports of substance use in 69 low-level substance users from the general community of Perth, Australia, volunteering for electrophysiological research, between 2002 and 2003. The participants included regular cannabis users and schizophrenia patients. Self-reports of recent use (last 24 hours) highly agreed with urine screen results (kappa = 0.91). Self-reports of past use (lifetime and last 12 months) had poor-moderate consistency based on correlations among dependence (measured with SDS, FTND, SMAST, CAGE), frequency, and use duration. Therefore, under some conditions, self-reports are valid for recent use and only moderately consistent for past substance use in general research participants.

Chronic cannabis use is associated with attention-modulated reduction in prepulse inhibition of the startle reflex in healthy humans.

Regardless of a wide research interest the nature of a relationship between cannabis use and schizophrenia is controversial. One of the physiological abnormalities in schizophrenia is attention-modulated deficit in prepulse inhibition (PPI), which is a normal reduction in the startle reflex magnitude when a non-startling stimulus (prepulse) precedes the startling stimulus (pulse). This experiment was designed to determine whether or not otherwise healthy people using cannabis would exhibit attention-modulated deficit in PPI. The startle reflex was recorded in carefully screened healthy humans attending to and ignoring auditory pulse and prepulse stimuli separated by short (20-200 ms) and long prepulse intervals (1600 ms). In contrast to 12 non-using controls, cannabis use in 16 healthy humans was associated with significant reduction in%PPI while attending to auditory stimuli, but not while ignoring them. The PPI was correlated with the duration of cannabis use but not with the concentration of cannabinoid metabolites in urine and the recency of cannabis use in the preceding 24 hours. Cannabis use was not associated with changes in prepulse facilitation of startle reflex magnitude (%PPF) at long prepulse intervals, prepulse facilitation of startle reflex latency and startle reflex magnitude in the absence of prepulses. These results suggest that chronic, but not acute, use of cannabis is associated with schizophrenia-like disruption in PPI in healthy controls. Such reduction in PPI is attention-dependent and does not reflect a global deficit in sensorimotor gating in cannabis users.