A review of eating disorders research in Mexico

The objective of this paper is to summarize research findings on eating disorders and the current state of the field in Mexico. Papers published in indexed journals and graduate dissertations were retrieved, using “eating disorders,” “anorexia nervosa,” “bulimia nervosa,” “body image,” “binge eating,” “restrained eating,” “weight and shape concern,” and “dieting” as keywords. These were combined with the Boolean operator “AND” with “Mexico” and “Latin America.” Findings are presented for epidemiology, the validity of assessment instruments, comorbidity, and risk factors. A national representative survey found a prevalence of 1.8% for bulimia nervosa, and no cases of anorexia nervosa. However, the lack of studies with confirmatory clinical interview and other national or regional representative samples makes it difficult to reach conclusions about the actual prevalence. A number of instruments for the detection of eating disorders and disordered eating have been validated for the Mexican population. The comorbidity of eating disorders in Mexico includes drug and alcohol abuse, obesity, and borderline personality disorder. Risk factors found included body weight and cultural pressure to be thin. Future lines of research should include epidemiological studies with representative samples and diagnosis confirmation, longitudinal studies, and the exploration of protective and risk factors specific to this population.     

Exercise dependence and associated disorders: A review

While the term exercise addiction has been largely rejected in favour of, for example, exercise dependence, the association of exercise with addiction stems from Glasser (1976) who differentiated between positive and negative addiction to running, being analogous to commitment and dependence, respectively. There are a number of possible explanations for exercise dependence, the more popular being based upon endorphin production and on personality. A key issue for research is to determine the threshold between commitment and dependence; that is, how much exercise is necessary to benefit mental health, and how much is too much? In addition, a holistic approach incorporating biological, social and situation-specific, as well as psychological factors, is supported in order to explain further the reasons for an exercise-dependent lifestyle. While ‘compulsive athleticism” (Yam et al., 1994) presents a cause for concern, and although it is not yet possible to identify, unequivocally the antecedents of this behaviour, it is proposed that a counselling approach to the problem of exercise dependence and associated negative self-perception may be timely.     

Neurocognitive dysfunction in children with sleep disorders

It is well known that adults with sleep disturbances frequently exhibit a wide range of neurocognitive decrements, and that these deficits are potentially reversible with effective treatment. However, the consequences of respiratory sleep disturbances on neurocognitive function in children have only recently been evaluated, and suggest a strong causal association between the episodic hypoxia and sleep fragmentation that characterize the disease and the emergence of reduced memory, attention and intelligence as well as a link to problematic and hyperactive behaviours and mood disturbances. This article takes a critical look at the current literature on these issues, reviews the major findings and discusses such findings in conjunction with those derived from pertinent animal models.     

Olfaction in autism spectrum disorders: A systematic review

Olfactory function is a well-known early biomarker for neurodegeneration and neural functioning in the adult population, being supported by a number of brain structures that could be dysfunctioning in neurodegenerative processes. Evidence has suggested that atypical sensory and, particularly, olfactory processing is present in several neurodevelopmental conditions, including autism spectrum disorders (ASDs). In this paper, we present data obtained by a systematic literature review, conducted according to PRISMA guidelines, regarding the possible association between olfaction and ASDs, and analyze them critically in order to evaluate the occurrence of olfactory impairment in ASDs, as well as the possible usefulness of olfactory evaluation in such conditions. The results obtained in this analysis suggested a possible involvement of olfactory impairment in ASDs, underlining the importance of olfactory evaluation in the clinical assessment of ASDs. This assessment could be potentially included as a complementary evaluation in the diagnostic protocol of the condition. Methods for study selection and inclusion criteria were specified in advance and documented in PROSPERO protocol #CRD42014013939.     

Affective disorders and aggression disorders: evidence for a common biological mechanism

Ever since the discovery that the classical antidepressants--tricyclics and MA oxidase inhibitors--exert an influence on central 5-HT, this neurotransmitter has been studied in depression, particularly in those forms responsive to this type of treatment. This chapter reviews the evidence in favor of a relationship between depression and central 5-HT dysfunctions. Most of the findings have been derived from patients with depression as the principal diagnosis. Some data have originated from patients suffering from a somatic illness and from depression as well. Both peripheral and central data are discussed. Although no single 5-HT-related finding in depression has so far been unequivocally established, the available evidence, in balance, justifies the tentative conclusion that disturbances in 5-HT metabolism can occur in depression. Lowered CSF 5-HIAA, the major indicator of disturbed central 5-HT metabolism in depression, has also been reported in aggression disorders, both in patients who had committed suicidal acts and in those with outward-directed aggression. The finding can not be explained by a concomitant state of depression. Rather than to discard the classical 5-HT-depression hypothesis, in favor of a 5-HT-aggression hypothesis, the hypothesis is launched that disturbances in serotonergic regulation can give rise to both mood and aggression disorders. This would provide a biological explanation for the clinical observation that those disorders frequently go hand in hand.     

Epidemiologic study of sleep disorders in Kuwaiti adolescents.

A sample of 2,574 volunteer Kuwaiti boys (n = 1,309) and girls (n = 1,265) in secondary schools were recruited. Their ages ranged from 14 to 18 years. 13 items were used to assess prevalence of insomnia, hypersomnia, nightmares, sleepwalking, sleep terror, and narcolepsy. Participants were requested to respond according to the past month on a 5-point scale. The summation of responses in the last two options, i.e., "Much" and "Very much" was considered as the point prevalence rates. Girls had significantly higher mean ratings than boys on the following items: difficulty initiating sleep, fitful and disturbed sleep, waking up several times, nightmares, and sleep terror, while boys had significantly higher mean ratings on sleepwalking and "watching TV causes naps or sleep." The point prevalence on all the items for boys ranged from 4.6% to 35.2%, and that for girls ranged between 1.0% and 37.5%. One should keep in mind that the present sample was not a clinical one.     

Sense of agency disturbances in movement disorders: A comprehensive review

Sense of agency refers to the experience that one’s self-generated action causes an event in the external environment. Here, we review the behavioural and brain evidence of aberrant experiences of agency in movement disorders, clinical conditions characterized by either a paucity or an excess of movements unrelated to the patient’s intention. We show that specific abnormal agency experiences characterize several movement disorders. Those manifestations are typically associated with structural and functional brain abnormalities. However, the evidence is sometimes conflicting, especially when considering results obtained through different agency measures. The present review aims to create order in the existing literature on sense of agency investigations in movement disorders and to provide a coherent overview framed within current neurocognitive models of motor awareness.     

Melatonin rhythm abnormalities and sleep disorders in the elderly

Biological aging is often associated with sleep problems and daytime napping. Complaints of difficulty in initiating and maintaining sleep, as well as daytime drowsiness, are more common in the elderly than in any other age group. This report reviews evidence that impaired melatonin secretion is associated with sleep disorders in old age. Circulating melatonin levels have been found to be significantly lower and onset and peak times have been delayed in elderly insomniacs as compared to age-matched control subjects. In view of these findings, we investigated the effects of melatonin treatment on melatonin-deficient insomnia in the elderly. From the results of our study, it seems likely that melatonin replacement therapy may be beneficial in the initiation and maintenance of sleep in this population.     

Habitual sleep duration and eating disorders in college students

To measure the relationship between habitual sleep duration and eating disorders, the responses of groups of 34 short- and 43 longer-sleeping college students to the EAT-26 Test were compared. The short-sleepers scored twice as high and were five times more likely to exhibit abnormal eating patterns than the longer-sleeping group.     

Evoked and event-related potentials in disorders of consciousness: A quantitative review

Sixty-one publications about evoked and event-related potentials (EP and ERP, respectively) in patients with severe Disorders of Consciousness (DoC) were found and analyzed from a quantitative point of view. Most studies are strongly underpowered, resulting in very broad confidence intervals (CI). Results of such studies cannot be correctly interpreted, because, for example, CI > 1 (in terms of Cohen’s d) indicate that the real effect may be very strong, very weak, or even opposite to the reported effect. Furthermore, strong negative correlations were obtained between sample size and effect size, indicating a possible publication bias. These correlations characterized not only the total data set, but also each thematically selected subset. The minimal criteria of a strong study to EP/ERP in DoC are proposed: at least 25 patients in each patient group; as reliable diagnosis as possible; the complete report of all methodological details and all details of results (including negative results); and the use of appropriate methods of data analysis. Only three of the detected 60 studies (5%) satisfy these criteria. The limitations of the current approach are also discussed.     

Cyber bullying among children with neurodevelopmental disorders: A systematic review

Children and young adults with neurodevelopmental disorders (ND) are at increased risk of bullying compared to typically developing peers. It is still unclear to what extent they are involved in cyber bullying. This systematic review aimed at studying the prevalence of cyber bullying as perpetrators, victims, or both (“bully-victims”) among students with ND in a school setting and in need of special education. The Web of Science, Scopus, ERIC, PsycINFO, PubMED, and Cochrane databases were searched including a manual search of reference lists, until February 24, 2018. Eight studies conducted in Europe, North America, the Middle East, and Australia were included reporting a prevalence of cyber-victimization among students with ND of 0%–41%, a prevalence of cyber-perpetration of 0%–16.7%, and a prevalence of bully-victims of 6.7%. Three out of five studies using control groups showed that students with ND might be more involved in cyber bullying overall compared to typically developing students. Students in segregated school settings report slightly higher prevalence rates of cyber bullying compared to students with ND in inclusive school settings, especially among girls. When comparing prevalence rates among studies using the same definition, we found similar prevalence rates. There was a tendency towards students with ND being more involved in cyber bullying compared to typically developing students, but this needs to be confirmed in future studies that should include control groups with typically developing students as well as validated and standardized measurements of cyber bullying and ND diagnoses.     

The personality disorders: A review and critique of contemporary assessment strategies

Despite the prevalence of personality disorders, only recently have they become the topic of extensive clinical research. Unfortunately, much of this research suffers from various assessment problems including poor interrater agreement, an overreliance on cross-sectional assessment, and inconsistencies across measures. The present review examines the strategies used to assess personality disorders. Three comprehensive tables are used to provide a quantitative review of existing studies. Although specific measures are examined, the focus remains on general strategies for assessment. Personality disorder assessment may be enhanced through the use of aggregation methods. Aggregating over raters can reduce the subjective biases inherent in any one person's perception. Aggregating data over time reduces the instability of personality assessment, while aggregating data across measures reduces the reliance on any one measure to assess personality disorders accurately. Thus, future research should be able to refine the strategies used to study personality disorders.     

A review of the role of empathy in violence risk in mental disorders

Despite an established link between certain mental disorders and violence, the origins of this are not always clear. Recent work has suggested a role for social cognition deficits in this relationship. We conducted a systematic literature search using EMBASE, SCOPUS, PsychINFO, Science Direct and Ovid Medline databases and search terms relating to empathy, violence and mental disorders. 15 studies were classified as assessing either theory of mind (ToM) (n = 6) or facial affect recognition (FAR) (n = 10). Better mentalizing ability may be linked with violence. Violent patients with schizophrenia perform worse than those with personality disorder, but outperform their non-violent counterparts on complex theory of mind tasks. Six studies examined facial affect recognition in violent psychopathy patients, three of which found impairments in high psychopathy patients. Four studies investigated FAR in violent schizophrenia patients, who again tended to outperform non-violent patients, though the evidence for specificity of emotion remains mixed. Empathy may play a mediating role in the relationship between violence and mental disorder. Current findings are limited by methodological inconsistencies. Future studies would benefit from more comprehensive assessments of violence and co-morbidities, and more standardized measures across studies.     

Circadian rhythm sleep disorders as a possible side effect of fluvoxamine

Sleep problems, day somnolence, and fatigue as a result of psychotropic drugs are very common. Psychiatrists usually consider these effects a result of insomnia and treat them by prescribing sleeping pills or other benzodiazepine agents. We describe here 10 cases of circadian rhythm sleep disorders (CRSD)--and not merely insomnia--as a possible side effect of fluvoxamine (FVA). Two other serotonin reuptake inhibitors, fluoxetine and clomipramine, did not induce CRSD in any of these 10 patients. We speculate that FVA-induced CRSD is caused by the effect of FVA on serotonin and melatonin levels in the central nervous system. CRSD as a side effect of FVA can be treated by replacing the suspected FVA or adding melatonin to a beneficial FVA treatment. Thus, it is important to be aware of possible iatrogenic CRSD in order to treat appropriately. Prospective studies are needed to confirm our observation and to study the influence of other psychotropic drugs on sleep-wake schedule.