Conditional Reasoning in Schizophrenic Patients.

Conditional reasoning (if p then q) is used very frequently in everyday situations. Conditional reasoning is impaired in brain-lesion patients, psychopathy, alcoholism, and polydrug dependence. Many neurocognitive deficits have also been described in schizophrenia. We assessed conditional reasoning in 25 patients with schizophrenia, 25 depressive patients, and 25 controls, using the Wason selection task in three different domains: social contracts, precautionary rules, and descriptive rules. Control measures included depression, anxiety, and severity of schizophrenia measures as a Verbal Intelligence Scale. Patients with schizophrenia were significantly impaired on all conditional reasoning tasks compared to depressives and controls. However, the social contract and precautions tasks yielded better results than the descriptive tasks. Differences between groups disappeared for social contract but remained for precautions and descriptive tasks when verbal intelligence was used as a covariate. These results suggest that domain-specific reasoning mechanisms, proposed by evolutionary psychologists, are relatively resilient in the face of brain network disruptions that impair more general reasoning abilities. Nevertheless, patients with schizophrenia could encounter difficulties understanding precaution rules and social contracts in real-life situations resulting in unwise risk-taking and misunderstandings in the social world.

The P300 component wave reveals differences in subclinical anxious-depressive states during bimodal oddball tasks: An effect of stimulus congruence.

OBJECTIVE: We previously found that using a bimodal oddball design with synchronized pairs of audio-visual stimuli increased the sensitivity of the P300 wave to subclinical differences in depression. We wondered: (1) whether these P300 modulations were due to facilitated discrimination of deviant vs. frequent stimuli and (2) whether congruency of the stimuli was necessary to produce this effect. METHOD: Two groups of participants (students displaying anxious-depressive tendencies as the subclinical group and healthy students as the control group) had to detect deviant stimuli among frequent stimuli in oddball tasks. Experiment 1 involved either single faces (Single condition) or two similar faces presented side-by-side (Double condition). Experiment 2 involved audio (A), visual (V), bimodal congruent (AVC), and bimodal incongruent (AVI) oddball tasks. RESULTS: While the easiest Double condition produced the fastest reaction times and shortest P300 latencies, there were no significant differences in P300 modulation between the groups in Experiment 1. In Experiment 2, P300 amplitudes of the control group were higher in response to AVC tasks than in response to unimodal (A or V) or AVI tasks. CONCLUSIONS: The increased sensitivity of the P300 wave to subclinical differences that we observed here is not related to an enhanced discrimination effect. However, during bimodal tasks, stimulus congruency is necessary for the appearance of the increased P300 sensitivity. SIGNIFICANCE: The impaired "bimodal congruence effect" in patients with subclinical depression/anxiety suggests these patients have altered integrative processes, which has potential implications for cognitive therapy.

Subclinical alexithymia modulates early audio-visual perceptive and attentional event-related potentials.

INTRODUCTION: Previous studies have highlighted the advantage of using audio-visual oddball tasks (instead of unimodal ones) in order to electrophysiologically index subclinical behavioral differences. Since alexithymia is highly prevalent in the general population, we investigated whether the use of various bimodal tasks could elicit emotional effects in low- vs. high-alexithymic scorers. METHODS: Fifty students (33 females and 17 males) were split into groups based on low and high scores on the Toronto Alexithymia Scale (TAS-20). During event-related potential (ERP) recordings, they were exposed to three kinds of audio-visual oddball tasks: neutral-AVN-(geometrical forms and bips), animal-AVA-(dog and cock with their respective shouts), or emotional-AVE-(faces and voices) stimuli. In each condition, participants were asked to quickly detect deviant events occurring amongst a train of repeated and frequent matching stimuli (e.g., push a button when a sad face-voice pair appeared amongst a train of neutral face-voice pairs). P100, N100, and P300 components were analyzed: P100 refers to visual perceptive and attentional processing, N100 to auditory ones, and the P300 relates to response-related stages, involving memory processes. RESULTS: High-alexithymic scorers presented a particular pattern of results when processing the emotional stimulations, reflected in early ERP components by increased P100 and N100 amplitudes in the emotional oddball tasks [P100: F (2, 48) = 20,319, p < 0.001; N100: F (2, 96) = 8,807, p = 0.001] as compared to the animal or neutral ones. Indeed, regarding the P100, subjects exhibited a higher amplitude in the AVE condition (8.717 µV), which was significantly different from that observed during the AVN condition (4.382 µV, p < 0.001). For the N100, the highest amplitude was found in the AVE condition (-4.035 µV) and the lowest was observed in the AVN condition (-2.687 µV, p = 0.003). However, no effect was found on the later P300 component. CONCLUSIONS: Our findings suggest that high-alexithymic scorers require heightened early attentional resources in comparison to low scorers, particularly when confronted with emotional bimodal stimuli.

Greater sensitivity of the P300 component to bimodal stimulation in an event-related potentials oddball task.

OBJECTIVE: Studies that explore neurophysiological correlates of psychiatric disorders have commonly used event-related potentials during a visual or an auditory oddball task with the main results being changes in the P300 component. In the present study, a bimodal oddball design with synchronized pairs of audio-visual stimuli was used to further improve the clinical sensitivity of the P300. METHODS: Two groups of healthy participants, one consisting of students displaying anxious-depressive tendencies and the other of control students, completed visual, auditory and two kinds of audio-visual oddball task (one using emotional stimuli and the other using geometrical figures and simple sounds), in which they had to detect deviant rare stimuli among more frequently presented standard stimuli as quickly as possible. Behavioral performance and P300 data were analyzed. RESULTS: The subjects with anxious and depressive tendencies had lower P300 amplitudes than controls, but only in the bimodal tasks. CONCLUSIONS: Although the two groups differed in their levels of anxiety and depression, only the bimodal tasks were able to identify these differences. SIGNIFICANCES: These results suggest that a bimodal oddball design should be used in future studies to increase the sensitivity of P300 differences for differentiating between healthy participants and those with clinical symptoms.

Conditional reasoning difficulties in polysubstance-dependent patients.

Polysubstance dependence has been associated with many neurocognitive impairments. The present study explored one of these deficits, namely conditional reasoning, using the Wason selection task. In healthy individuals, social contract and precautionary content improve conditional reasoning performance compared with descriptive or abstract content. Twenty-two recently detoxified polysubstance-dependent patients were compared with 22 controls matched for sex, age, and education level on their performance on the Wason selection task across problems involving social contract, precautionary, and descriptive conditional rules, controlling for depression, anxiety levels, and verbal intelligence. Conditional reasoning on descriptive and social contract rules was severely impaired in polysubstance-dependent patients. Precautionary reasoning was also impaired, but to a lesser degree than the other modalities of conditional reasoning. These results may reflect a toxic effect of chronic multiple-drug consumption on the prefrontal areas of the brain. Alternatively, conditional reasoning difficulties could be present, at least partially, before polysubstance dependence onset. This population may have difficulties properly understanding social contracts in real-life settings, suggesting a potential target for clinical intervention.

Impaired conditional reasoning in alcoholics: a negative impact on social interactions and risky behaviors?

AIMS: To study the 'social brain' in alcoholics by investigating social contract reasoning, theory of mind and emotional intelligence. DESIGN: A behavioral study comparing recently detoxified alcoholics with normal, healthy controls. SETTING: Emotional intelligence and decoding of emotional non-verbal cues have been shown to be impaired in alcoholics. This study explores whether these deficits extend to conditional reasoning about social contracts. PARTICIPANTS: Twenty-five recently detoxified alcoholics (17 men and eight women) were compared with 25 normal controls (17 men and eight women) matched for sex, age and education level. MEASUREMENTS: Wason selection task investigating conditional reasoning on three different rule types (social contract, precautionary and descriptive), revised Reading the Mind in the Eyes Test, Trait Emotional Intelligence Questionnaire (modified version) and additional control measures. FINDINGS: Conditional reasoning was impaired in alcoholics. Performance on descriptive rules was not above chance. Reasoning performance was markedly better on social contract and precautionary rules, but this performance was still significantly lower than in controls. Several emotional intelligence measures were lower in alcoholics compared to controls, but these were not correlated with reasoning performance. CONCLUSIONS: Conditional reasoning, including reasoning about social contracts and emotional intelligence appear to be impaired in alcoholics. Impairment seems to be particularly severe on descriptive rules. Impairment in social contract reasoning might lead to misunderstandings and frustration in social interactions, and reasoning difficulties about precautionary rules might contribute to risky behaviors in this population.