José Manuel Rodríguez-Sánchez

Construct validity of the Trail Making Test: Role of task-switching, working memory, inhibition/interference control, and visuomotor abilities

The aim of this study was to clarify which cognitive mechanisms underlie Trail Making Test (TMT) direct and derived scores. A comprehensive review of the literature on the topic was carried out to clarify which cognitive factors had been related to TMT performance. Following the review, we explored the relative contribution from working memory, inhibition/interference control, task-switching ability, and visuomotor speed to TMT performance. Forty-one healthy old subjects participated in the study and performed a battery of neuropsychological tests including the TMT, the Digit Symbol subtest [Wechsler Adult Intelligence Scale (Third Version) (WAIS-III)], a Finger Tapping Test, the Digits Forward and Backward subtests (WAIS-III), Stroop Test, and a task-switching paradigm inspired in the Wisconsin Card Sorting Test. Correlation and regression analyses were used in order to clarify the joint and unique contributions from different cognitive factors to the prediction of TMT scores. The results suggest that TMT-A requires mainly visuoperceptual abilities, TMT-B reflects primarily working memory and secondarily task-switching ability, while B-A minimizes visuoperceptual and working memory demands, providing a relatively pure indicator of executive control abilities.

Antipsychotic-Induced Weight Gain in Chronic and First-Episode Psychotic Disorders : A Systematic Critical Reappraisal

Antipsychotic-induced weight gain is an important issue in the treatment of psychotic illnesses, and affects 80% of individuals being treated with antipsychotic drugs. However, the true dimension of weight gain and many accepted ‘facts’ in this area remain unclear as most research has been conducted in short-term trials and has included individuals receiving prolonged antipsychotic treatment.This review aims to systematically and critically review the evidence on weight gain induced by the two leading second-generation antipsychotics (olanzapine and risperidone) and the most widely researched first-generation antipsychotic (haloperidol) in patients with chronic and first-episode psychotic disorders.Weight gain was 3- to 4-fold greater in studies that included young patients with limited previous exposure to antipsychotic agents in both short-term studies (7.1–9.2 kg for olanzapine, 4.0–5.6 kg for risperidone and 2.6–3.8 kg for haloperidol vs 1.8–5.4 kg, 1.0–2.3 kg and 0.01–1.4 kg, respectively, in studies that included patients with chronic psychotic disorders) and long-term trials (10.2–15.4 kg for olanzapine, 6.6–8.9 kg for risperidone and 4.0–9.7 kg for haloperidol vs 2.0–6.2 kg, 0.4–3.9 kg and −0.7 to 0.4 kg, respectively). The same disparity was observed regarding the proportion of patients increasing their baseline weight by ≥7% (the cut-off for clinically significant weight gain).Recent studies carried out in young patients with first-episode psychosis (FEP), along with methodological artefacts in studies of chronic populations, suggest that the magnitude of weight gain reported by much of the literature could in fact be an underestimation of the true magnitude of this adverse effect. Although antipsychotics present idiosyncratic patterns of weight gain, they may also generate similar absolute gains.

White Matter Integrity and Cognitive Impairment in First-Episode Psychosis

OBJECTIVE Impaired cognitive function has been identified as a core feature of schizophrenia. However, a significant proportion of patients do not show any cognitive deficits. The aim of this study was to assess if there were differences in white matter integrity between patients with and without cognitive impairment. METHOD A diffusion tensor imaging study and neurocognitive assessment were conducted in 49 patients with first-episode psychosis and 41 healthy comparison subjects. Subjects were assessed using the Continuous Performance Test, the Grooved Pegboard Test, the Rey Auditory Verbal Learning Test, and the Trail Making Test Part B. For each test, the patient sample was subdivided according to performance, with those scoring more than one standard deviation below the normative mean categorized as impaired. For each cognitive domain, white matter fractional anisotropy in deficit and nondeficit subgroups was compared using a voxel-based analysis. A nonparametric statistical method, controlling for multiple comparisons, was applied. RESULTS Impairment on the Trail Making Test Part B was associated with reduced fractional anisotropy in the right/left anterior thalamic radiation and inferior fronto-occipital fasciculus, forceps minor, and left superior and inferior longitudinal fasciculi. Patients exhibiting Grooved Pegboard Test impairment showed reduced fractional anisotropy in the forceps minor, inferior fronto-occipital fasciculus, anterior thalamic radiation, and corticospinal and corticopontine tracts. Impaired performance on the Rey Auditory Verbal Learning Test and Continuous Performance Test was not associated with significant differences in fractional anisotropy. CONCLUSION Deficits in executive and motor functioning in patients with first-episode psychosis are associated with reductions in white matter integrity in the major fasciculi that connect the frontal and temporal cortices as well as in pathways connecting cortical and subcortical regions. Their presence at the onset of illness, in minimally medicated patients, indicates that these findings are not attributable to effects of chronic illness or its treatment.

Cognitive dysfunction in first-episode psychosis: the processing speed hypothesis

BACKGROUND Speed of processing is a cognitive process underlying cognitive dysfunction in people with chronic schizophrenia. AIMS To investigate the contribution of speed of processing to the cognitive deficits observed in a representative large sample with first-episode schizophrenia. METHOD People with a diagnosis of first-episode schizophrenia-spectrum disorders (n=26) and healthy controls (n=28) were compared on several cognitive measures before and after controlling for speed of processing. RESULTS Before controlling for speed of processing, patients and controls differed significantly on all cognitive measures. All significant differences in cognitive functioning disappeared when the result of the Digital Symbol Substitution Test was included as an additional covariate. CONCLUSIONS Speed of information processing may be considered a core cognitive deficit in schizophrenia and might be mediating a broader diversity of cognitive disturbances.

Epidemiological factors associated with treated incidence of first‐episode non‐affective psychosis in Cantabria: insights from the Clinical Programme on Early Phases of Psychosis

Aim: The aim of the study was to analyse the treated incidence of schizophrenia in Cantabria (Northern Spain) and the sociodemographic risk factors associated with the illness onset.

Reduced thalamic volume in first-episode non-affective psychosis: Correlations with clinical variables, symptomatology and cognitive functioning

Structural studies have inconsistently shown the presence of thalamic volume differences in patients with schizophrenia. However, only a few studies have examined the relation between thalamic structure and clinical and cognitive variables in early phases of the illness. Thalamic volumes in right-handed minimally treated first episode patients with non-affective psychosis (N=61) relative to those of right-handed healthy comparison subjects (N=40) were measured. Thalamic volumes in the right and left hemispheres and total thalamic volume were automatically segmented and analyzed using BRAINS2. Analysis of covariance was used to control for intracranial volume. Clinical symptoms were assessed by total scores of BPRS, SAPS and SANS. The relationship between three cognitive dimensions (verbal learning and memory, speed processing/executive functioning and sustained attention/vigilance), and thalamic volume was evaluated. The impact of the duration of untreated illness, untreated psychosis and prodrome period in thalamic morphometry was also explored. Right, left, and total thalamic volumes of the patients with non-affective psychosis were significantly smaller than those of the healthy subjects. Larger thalamic volumes were associated with an earlier age of onset, a poorer cognitive functioning and a more severe negative symptomatology. Thalamic volumetric differences between patients with non-affective psychosis and healthy controls are already present at early phases of the illness. However, further investigations are warranted to fully clarify the relationship between those structural anomalies and clinical and cognitive outcomes.

Prefrontal cognitive functions in stabilized first-episode patients with schizophrenia spectrum disorders: A dissociation between dorsolateral and orbitofrontal functioning

Specific prefrontal cognitive impairments have been reported in first-episode and chronic schizophrenia. We sought to investigate potential impairments in specific prefrontal cortical cognitive functions among stabilized patients with a first-episode of schizophrenia. A sample of 80 individuals with a first-episode of schizophrenia spectrum disorders and 22 healthy volunteers underwent a neurocognitive battery assessing orbitofrontal (OFC) [The Iowa Gambling Task (GT)], and dorsolateral prefrontal (DLPFC) functions (WAIS III Backward digits, verbal fluency test (FAS), and Trail Making Test). Cognitive data were obtained following stabilization of acute psychotic symptoms. Clinical symptoms after six weeks of treatment were assessed by using the SAPS and SANS scales. While there were no significant group differences in overall scores and in the profile of progress of performance along periods on the GT, patient group showed a significant impairment when performing DLPFC tasks. Only FAS score was correlated to the severity of negative symptomatology. The OFC functions are unimpaired at the early phases of psychosis and in contrast there is a significant deficit in DLPFC functions in first-episode of schizophrenia.

Neuropsychological functioning and brain structure in schizophrenia

Cognitive deficits are core features of schizophrenia that are already evident at early phases of the illness. The study of specific relationships between cognition and brain structure might provide valuable clues about neural basis of schizophrenia and its phenomenology. The aim of this article was to review the most consistent findings of the studies exploring the relationships between cognitive deficits and brain anomalies in schizophrenia. Besides several important methodological shortcomings to bear in mind before drawing any consistent conclusion from the revised literature, we have attempted to systematically summarize these findings. Thus, this review has revealed that whole brain volume tends to positively correlate with a range of cognitive domains in healthy volunteers and female patients. An association between prefrontal morphological characteristics and general inability to control behaviour seems to be present in schizophrenia patients. Parahippocampal volume is related to semantic cognitive functions. Thalamic anomalies have been associated with executive deficits specifically in patients. Available evidence on the relationship between cognitive functions and cerebellar structure is still contradictory. Nonetheless, a larger cerebellum appears to be associated with higher IQ in controls and in female patients. Enlarged ventricles, including lateral and third ventricles, are associated with deficits in attention, executive and premorbid cognitive functioning in patients. Several of these reported findings seem to be counterintuitive according to neural basis of cognitive functioning drawn from animal, lesion, and functional imaging investigations. Therefore, there is still a great need for more methodologically stringent investigations that would help in the advance of our understanding of the cognition/brain structure relationships in schizophrenia.

Neurocognitive effectiveness of haloperidol, risperidone, and olanzapine in first-episode psychosis: a randomized, controlled 1-year follow-up comparison.

OBJECTIVE To investigate the neurocognitive effectiveness of haloperidol, risperidone, and olanzapine in first-episode schizophrenia-spectrum disorders. METHOD This prospective, randomized, open-label study was conducted from February 2001 to February 2005. Data for the present investigation were obtained from a large epidemiologic and 3-year longitudinal intervention program of first-episode psychosis (DSM-IV criteria) conducted at the outpatient clinic and the inpatient unit at the University Hospital Marques de Valdecilla, Santander, Spain. One hundred four patients randomly assigned to haloperidol (N = 35), olanzapine (N = 30), or risperidone (N = 39) who completed clinical and cognitive evaluations at baseline, 6 months, and 1 year were included in the final analysis. Thirty-seven healthy individuals were also longitudinally assessed. A neuropsychological battery that comprised 9 cognitive domains was used. The contribution of clinical changes, concomitant medications, and the severity of motor side effects to cognitive changes was controlled. The main outcome measure was cognitive changes at 1-year follow-up. RESULTS The 3 treatment groups showed a significant improvement in cognitive scores after 1 year. The differential cognitive effectiveness between antipsychotics was insignificant. The magnitude of cognitive changes was similar in the 3 treatment groups and controls, although a greater improvement on the Finger Tapping Test, Trail Making Test B, and Rey Complex Figure Test was found in the treatment groups. Clinical changes, use of concomitant medications, and the emergence of motor side effects did not significantly account for cognitive changes over time. CONCLUSION Haloperidol, olanzapine, and risperidone were equally effective in treating cognitive deficits of psychosis. The effect of practice clearly contributes to cognitive score improvements after treatment with antipsychotics. Our results provide important information regarding the practical utility of antipsychotic treatments to improve cognition and could have implications for developing novel approaches for cognitive pharmacotherapy in schizophrenia.

Effect of antipsychotic drugs on brain morphometry. A randomized controlled one-year follow-up study of haloperidol, risperidone and olanzapine.

BACKGROUND The effect of antipsychotic drugs on brain morphology is under debate. Here we investigate the effects of risperidone, olanzapine and low doses of haloperidol on cortical and subcortical morphometry in first episode drug naïve patients with non-affective psychosis. METHODS Morphological variables were measured in three treatment groups (haloperidol=18; risperidone=16; olanzapine=18) and in healthy subjects (N=38) at baseline and after one year. The relationship between brain morphometric changes and changes in clinical scores was also assessed. RESULTS At one year, the three antipsychotics had had an equal effect on the gray matter cortical structure, overall and lobes (all ps>0.121.). A significant time-by-group interaction was found in lateral ventricle volume (F2,47=5.65; p=0.006). Post-hoc comparisons revealed a significant increase in lateral ventricles in patients treated with risperidone (p=0.009). Patients exposed to atypicals (olanzapine and risperidone) exhibited a decrease in caudate nucleus volume (p=0.001). In general, brain changes did not account in any significant manner for clinical changes over time in any treatment group. CONCLUSIONS We conclude that low doses of haloperidol, risperidone and olanzapine seem to have an equal effect on the gray matter cortical structure after 1 year of treatment. In contrast to typical antipsychotics, atypicals have differential effects on lateral ventricle and caudate nucleus volumes.