The effects of acute tryptophan depletion on impulsivity and mood in adolescents engaging in non-suicidal self-injury

Neurolipidomics in schizophrenia: A not so well-oiled machine

Most patients with schizophrenia (SCZ) do not exhibit violent behaviors and are more likely to be victims rather than perpetrators of violent acts. However, a subgroup of forensic detainees with SCZ exhibit tendencies to engage in criminal violations. Although numerous models have been proposed, ranging from substance use, serotonin transporter gene, and cognitive dysfunction, the molecular underpinnings of violence in SCZ patients remains elusive. Lithium and clozapine have established anti-aggression properties and recent studies have linked low cholesterol levels and ultraviolet (UV) radiation with human aggression, while vitamin D3 reduces violent behaviors. A recent study found that vitamin D3, omega-3 fatty acids, magnesium, and zinc lower aggression in forensic population. In this review article, we take a closer look at aryl hydrocarbon receptor (AhR) and the dysfunctional lipidome in neuronal membranes, with emphasis on cholesterol and vitamin D3 depletion, as sources of aggressive behavior. We also discuss modalities to increase the fluidity of neuronal double layer via membrane lipid replacement (MLR) and natural or synthetic compounds. This article is part of the Special Issue on "Personality Disorders".

Testing the validity and reliability of the Matching Familiar Figures Test-2021: An updated behavioral measure of reflection–impulsivity

The Matching Familiar Figures Test (MFFT) is a well-known and extensively used behavioral measure of reflection-impulsivity. However, the instrument has several deficiencies, including images designed for school-age children in the United States during the 1960s. Most importantly, an adult version of the instrument is currently unavailable and the lack of a single repository for the images raises questions regarding the MFFT’s validity and reliability. We developed a 21st century version of the MFFT using images that are familiar to adults and reside in a freely accessible repository. We conducted two studies examining validity and reliability issues. In Study 1, participants interacting with the MFFT-2021, versus those interacting with the original MFFT20, spent more time on the task, took more time in making their first response, and were more likely to complete the task without errors, even though the average number of errors was higher than the comparison group. The coherence of these results is evidence of convergent validity. Regarding predictive validity, the MFFT-2021 remained a reliable predictor of rational thinking, such that participants who demonstrated more reflection (less impulsivity) tended to avoid rational thinking errors. Also, performance on the MFFT-2021 predicted higher quality judgments in processing job characteristic cues with embedded interactions, a form of configural information processing. We also found evidence of concurrent validity: performance on the MFFT-2021 differed in a predictable manner for participants grouped by their performance on the Cognitive Reflection Test. In Study 2, we tested discriminant validity by comparing participant performance on the MFFT-2021 to their performance on the Information Sampling Task (IST), another behavioral measure of reflection-impulsivity used in studies of psychopharmacological and addiction behaviors. For our participants (undergraduate business students), we found that the MFFT was a stronger predictor of performance on rational thinking tasks, and, contrary to prior studies, our exploratory factor analysis identified separate factors for the MFFT-2021 and the IST, supporting discriminant validity, indicating that these two instruments measure different subtypes of reflection-impulsivity.

Clinical Severity and Calcium Metabolism in Patients with Bipolar Disorder

Parathyroid hormone (PTH), vitamin D and serum calcium play a key role in several physiological and pathological conditions. Vitamin D and PTH receptors are largely expressed in the central nervous system and are involved in the modulation of inflammatory responses. Few studies investigated the association between calcium homeostasis imbalance and psychiatric disorders. This study aims to assess calcium homeostasis imbalance in patients with bipolar disorder (BD) and its impact on clinical outcome. We recruited 199 patients with BD, who were administered with validated assessment instruments to investigate depressive, manic and anxiety symptoms, affective temperaments, childhood trauma and global functioning. Serum calcium, vitamin D and PTH levels were assessed in all patients. Levels of PTH correlated with several clinical characteristics, including the diagnosis of bipolar disorder type I (BD-I), the presence of psychotic symptoms, lithium treatment, suicidality, total number of acute episodes and of hospitalizations (p < 0.0001) and seasonality (p < 0.05). At the regression analyses, higher levels of PTH were predicted by early age at onset, number of hospitalizations, aggressive behaviors (p < 0.05), higher Childhood Trauma Questionnaire total score (CTQ) (p < 0.001) and treatment with lithium (p = 0.01). Our findings suggest that the calcium homeostasis could play a role in BD patients, and that PTH levels are correlated with the clinical severity of the disorder.

Impulsivity and Response Latency in Non-Suicidal Self-Injury: The Role of Negative Urgency in Emotion Regulation

Impulsivity is thought to be a contributing factor in non-suicidal self-injury (NSSI), yet the research is limited and inconsistent. In particular, little is known about how impulsivity is associated with response latency between initial urge and later self-injury, emotion regulation processes, or severity of NSSI. In this study, we tested group differences between participants with and without a history of NSSI on a questionnaire measure of impulsivity. In addition, we tested hypothesized correlations between impulsivity and relevant variables within the NSSI sample using questionnaires and self-reported response latency between urge and injury. Participants included 159 undergraduate students, 84 with an NSSI history and 75 without an NSSI history. Results indicated greater impulsivity on facets of Urgency and (lack of) Perseverance for the NSSI group. Within the NSSI sample, facets of impulsivity were associated with difficulties in emotion regulation and NSSI severity, but not response latency. In addition, response latency, a possible behavioral marker of impulsivity, was not associated with emotion regulation processes or NSSI frequency. These results suggest that higher scores on self-report measures of impulsivity, but not behavioral response latency measures, are associated with emotion regulation processes in individuals who self-injure.

Behavior and inhibitory control in children with prenatal exposure to antidepressants and medically untreated depression

PURPOSE

The present study investigates child development following prenatal exposure to maternal use of selective serotonin reuptake inhibitors (SSRIs; N = 28), versus prenatal exposure to medically untreated depression (N = 42), and no exposure (N = 33).

METHODS

When the children reached 5-6 years of age, child cognitive abilities were measured using selected tests from Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-r), Neuropsychological Assessment II (NEPSY-II), and the Attention Network Test. Maternal reports of child behavioral problems were collected using the Child Behavior Checklist (CBCL).

CONCLUSION

Analyses of variance revealed no effects of prenatal exposure to depression or SSRIs upon general cognition or inhibition. Regarding behavioral problems, there was a significant negative association between both SSRI and depression exposure upon externalizing, and between SSRI exposure and internalizing problems. The results are interpreted in light of theories on interactive specialization and reactivity.

The serotonin transporter in psychiatric disorders: insights from PET imaging

Over the past 20 years, psychotropics affecting the serotonergic system have been used extensively in the treatment of psychiatric disorders. Molecular imaging, in particular PET, has allowed for elucidation of the essential contribution of the serotonin transporter to the pathophysiology of various psychiatric disorders and their treatment. We review studies that use PET to measure cerebral serotonin transporter activity in psychiatric disorders, focusing on major depressive disorder and antidepressant treatment. We also discuss opportunities and limitations in the application of this neuroimaging method in clinical practice. Although results from individual studies diverge, meta-analysis indicates a trend towards reduced serotonin transporter availability in patients with major depressive disorder. Inconsistencies in results might suggest symptom heterogeneity in major depressive disorder and might therefore be relevant for stratification of patients into clinical subsets. PET has enabled the elucidation of mechanisms of response to selective serotonin reuptake inhibitors (SSRIs) and hence provides a basis for rational pharmacological treatment of major depressive disorder. Such imaging studies have also suggested that the pattern of serotonin transporter binding before treatment might predict response to antidepressant treatment, which could potentially be clinically useful in the future. Additionally, this Review discusses PET studies investigating the serotonin transporter in anxiety, obsessive-compulsive disorder, and eating disorders. Few studies have shown changes in serotonin transporter activity in schizophrenia and attention deficit hyperactivity disorder. By showing the scarcity of data in these psychiatric disorders, we highlight the potential for further investigation in this field.

Impulsivity and nonsuicidal self-injury: A review and meta-analysis

Nonsuicidal self-injury (NSSI; direct self-injury without lethal intent) often is thought to be associated with impulse control problems. Recent research, however, offers conflicting results about whether impulsivity is a risk factor for NSSI engagement. To disentangle findings on the link between impulsivity and NSSI, an extensive review of the literature was conducted using several electronic databases (i.e., PsychInfo, PsychArticles, ERIC, CINAHL, and MEDLINE). In total, 27 studies that met the specific inclusion criteria were identified. Results of a meta-analysis revealed that individuals who engaged in NSSI self-reported greater impulsivity than individuals who did not engage in NSSI, and that this effect was most consistent for measures of negative urgency. In contrast, there was little evidence of an association between lab-based measures of impulsivity (e.g., Go/No-Go, Stop/Signal Task) and NSSI. Moreover, the link between impulsivity and NSSI found for self-report measures was sometimes eliminated when other risk factors for NSSI were controlled (e.g., abuse, depression, post-traumatic stress disorder). In addition to integrating findings, the present review provides several explanations for the discrepancies in findings between studies employing self-report versus lab-based measures of impulsivity. To conclude, several specific recommendations for future research directions to extend the literature on impulsivity and NSSI are offered.

Vitamin D and the omega-3 fatty acids control serotonin synthesis and action, part 2: relevance for ADHD, bipolar disorder, schizophrenia, and impulsive behavior

Serotonin regulates a wide variety of brain functions and behaviors. Here, we synthesize previous findings that serotonin regulates executive function, sensory gating, and social behavior and that attention deficit hyperactivity disorder, bipolar disorder, schizophrenia, and impulsive behavior all share in common defects in these functions. It has remained unclear why supplementation with omega-3 fatty acids and vitamin D improve cognitive function and behavior in these brain disorders. Here, we propose mechanisms by which serotonin synthesis, release, and function in the brain are modulated by vitamin D and the 2 marine omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Brain serotonin is synthesized from tryptophan by tryptophan hydroxylase 2, which is transcriptionally activated by vitamin D hormone. Inadequate levels of vitamin D (∼70% of the population) and omega-3 fatty acids are common, suggesting that brain serotonin synthesis is not optimal. We propose mechanisms by which EPA increases serotonin release from presynaptic neurons by reducing E2 series prostaglandins and DHA influences serotonin receptor action by increasing cell membrane fluidity in postsynaptic neurons. We propose a model whereby insufficient levels of vitamin D, EPA, or DHA, in combination with genetic factors and at key periods during development, would lead to dysfunctional serotonin activation and function and may be one underlying mechanism that contributes to neuropsychiatric disorders and depression. This model suggests that optimizing vitamin D and marine omega-3 fatty acid intake may help prevent and modulate the severity of brain dysfunction.

Overlapping genetic and environmental influences on nonsuicidal self-injury and suicidal ideation: different outcomes, same etiology?

IMPORTANCE

Nonsuicidal self-injury (NSSI) and suicidal self-injury are very harmful behaviors and are associated with several psychiatric disorders. In the recently developed fifth edition of the DSM, NSSI and suicidal behavior disorder are for the first time introduced as conditions in their own right instead of symptoms of other psychiatric disorders. It is unclear to what extent NSSI and suicidal self-injury share the same underlying biological mechanisms and are influenced by the same environmental factors.

OBJECTIVE

To determine the relative importance of genetic and environmental influences on the variation in NSSI and suicidal ideation and their covariation.

DESIGN, SETTING, AND PARTICIPANTS

Classical twin design using a sample of 10,678 male and female adult twins (mean [SD] age, 32.76 [6.99] years) from the Australian Twin Registry, a population-based twin registry. Between 1996 and 2009, the twins participated in semistructured telephone interviews that primarily focused on psychiatric disorders.

MAIN OUTCOMES AND MEASURES

Lifetime presence of self-reported NSSI and suicidal ideation. RESULTS The prevalences of NSSI and suicidal ideation were 4.7% and 26.5%, respectively, and individuals who engaged in self-harm were much more likely to report suicidal ideation (odds ratio = 8.39; 95% CI, 6.84-10.29). Results from a bivariate genetic model indicated that genetic factors explain a substantial part of the variance in both NSSI (37% for men and 59% for women) and suicidal ideation (41% for men and 55% for women), while residual influences (including nonshared environmental influences and measurement error) explain the remainder of the variance. Shared (family) environment did not seem to play a role. Moreover, both behaviors were strongly correlated (r = 0.49 for men and 0.61 for women), and this correlation was largely explained by overlapping genetic influences (76% for men and 62% for women), whereas residual influences accounted for the remainder of the phenotypic correlation.

CONCLUSIONS AND RELEVANCE

Results indicated that the substantial correlation between NSSI and suicidal ideation is largely driven by overlapping genetic factors, suggesting that the 2 behaviors share similar biological underpinnings. Overlapping residual influences also explain part of the covariance between the 2 traits. Future research should further investigate which genetic and environmental influences underlie the vulnerability to NSSI and suicidal ideation.

Sleep problems and hospitalization for self-harm: a 15-year follow-up of 9,000 Norwegian adolescents. The Young-HUNT Study

OBJECTIVES

To investigate the association between sleeping problems in adolescence and subsequent hospital admission for self-harm (SH).

DESIGN

Prospective cohort study, linking health survey information on sleep problems to hospital-based patient records.

SETTING

Residents of Nord-Trøndelag County, Norway, aged 13-19 years in 1995-97.

PATIENTS OR PARTICIPANTS

10,202 adolescents were invited to participate in the Young-HUNT study; 8,983 (88%) completed the health survey.

MEASUREMENTS AND RESULTS

10% of participants reported difficulties initiating sleep, 4% reported early morning wakening. Ninety-eight participants (27% male) were hospitalized following SH over a mean 12 years follow-up. Difficulties initiating sleep/early morning wakening were associated with increased risk of SH (HR 2.11, 95% CI 1.29-3.46, sex- and age-adjusted) compared with no problems, yet coexistent symptoms of combined anxiety/depression explained most of the association with sleep problems (fully adjusted HR 1.19, 95% CI 0.66-2.16). The HR of combined difficulties initiating sleep/early morning wakening differed in those with and without anxiety/depression at baseline (P interaction = 0.03); among those without caseness symptoms of anxiety/depression it was 5.58 (95% CI 2.02-15.40), while in those with caseness symptoms of anxiety/ depression it was 0.82 (95% CI 0.19-3.44).

CONCLUSIONS

Sleep problems are common among Norwegian adolescents. The strong association between sleep problems and subsequent hospitalization for self-harm could mainly be related to coexistent symptoms of anxiety and depression. Prevention of adolescent sleep problems, anxiety and depression should be targeted when seeking to reduce and prevent self-harm.

From passive overeating to "food addiction": a spectrum of compulsion and severity

A psychobiological dimension of eating behaviour is proposed, which is anchored at the low end by energy intake that is relatively well matched to energy output and is reflected by a stable body mass index (BMI) in the healthy range. Further along the continuum are increasing degrees of overeating (and BMI) characterized by more severe and more compulsive ingestive behaviours. In light of the many similarities between chronic binge eating and drug abuse, several authorities have adopted the perspective that an apparent dependence on highly palatable food-accompanied by emotional and social distress-can be best conceptualized as an addiction disorder. Therefore, this review also considers the overlapping symptoms and characteristics of binge eating disorder (BED) and models of food addiction, both in preclinical animal studies and in human research. It also presents this work in the context of the modern and "toxic" food environment and therein the ubiquitous triggers for over-consumption. We complete the review by providing evidence that what we have come to call "food addiction" may simply be a more acute and pathologically dense form of BED.