Serotonin transporter promoter gain-of-function genotypes are linked to obsessive-compulsive disorder

[Formula: see text] Can psychopathy be prevented? Clinical, neuroimaging, and genetic data: an exploratory study

The aim of the study was to explore the relationship among brain functional activations elicited by an emotional paradigm, clinical scores (PTSD, anxiety, and depression), psychopathic traits, and genetic characteristics (5-HTTLPR) in a group of severely maltreated children compared to a healthy control group before and after the implementation of a Trauma Focused-Cognitive Behavioral Therapy. The final sample consisted of an experimental group of 14 maltreated children (mean age = 8.77 years old, S.D. = 1.83) recruited from a non-governmental shelter in Mexico City for children who had experienced child abuse and a control group of 10 children from the general population (mean age = 9.57 years old, S.D. = 1.91). Both groups were matched according to age and gender and were assessed before and after the implementation of the aforementioned therapy by means of clinical scales and an emotional paradigm that elicited brain activations which were recorded through functional magnetic resonance imaging. Genotyping of the 5-HTTLPR polymorphism was made at first assessment. A region of interest analysis showed amygdala hyperactivation during exposure to fear and anger stimuli in the maltreated children before treatment. Following therapy, a decrease in brain activity as well as a decrease in clinical symptoms were also observed. 5-HTTLPR polymorphism did not show any effect on the severity of clinical symptoms in maltreated children. Trauma-Focused Behavioral Therapy may help reorganize the brain's processing of emotional stimuli. These observations reveal the importance of an early intervention when the mechanisms of neuroplasticity may be still recruited.

DNA Sequence Variations Affecting Serotonin Transporter Transcriptional Regulation and Activity: Do They Impact Alcohol Addiction?

Genetic features of alcohol dependence have been extensively investigated in recent years. A large body of studies has underlined the important role of genetic variants not only in metabolic pathways but also in the neurobiology of alcohol dependence, mediated by the neuronal circuits regulating reward and craving. Serotonin transporter (5-HTT), encoded by the SLC6A4 gene (Solute carrier family 6-neurotransmitter transporter-member 4), is targeted by antidepressant drugs such as selective serotonin reuptake inhibitors (SSRIs) and plays a pivotal role in serotoninergic transmission; it has been associated with psychiatric diseases and alcohol dependence. Transcriptional regulation and expression of 5-HTT depend not only on epigenetic modifications, among which DNA methylation (CpG and non-CpG) is primarily involved, but also on sequence variations occurring in intron/exon regions and in untranslated regions in 5' and 3', being the first sequences important for the splicing machinery and the last for the binding of transcription factors and micro RNAs. This work intends to shed light on the role of sequence variations known to affect the expression or function of 5-HTT in alcohol-dependent individuals. We found a statistically significant difference in the allelic (p = 0.0083) and genotypic (p = 0.0151) frequencies of the tri-allelic polymorphism, with higher function alleles and genotypes more represented in the control population. Furthermore, we identified three haplotypes more frequent in subjects with AUD (p < 0.0001) and one more frequent in the control population (p < 0.0001). The results obtained for the tri-allelic polymorphism in alcohol dependence confirm what is already present in part of the literature. The role of haplotypes requires further studies to be clarified.

Evolution of threat response-related polymorphisms at the SLC6A4 locus in callitrichid primates

Variation in an upstream repetitive region at the SLC6A4 locus, which encodes the serotonin transporter, is associated with anxiety-related behaviour in a few primate species, including humans and rhesus macaques, and has been suggested to be related to ecological adaptability among macaques. In this study, we investigate evolution of SLC6A4 polymorphisms associated with anxiety-related behaviour in common marmosets (Callithrix jacchus). Assaying variation in the SLC6A4 repeat region across 14 species in eight genera of callitrichid primates (marmosets and tamarins), we find large interspecific variation in the number of repeats present (24-43). The black tufted-ear marmoset (C. penicillata) has sequence polymorphisms similar to those found in the common marmoset, which is its sister species, and no other species has intraspecific variation at these sites. We conclude that, similar to humans and macaques, the functional polymorphism at SLC6A4 in common marmosets has a recent evolutionary origin, and that the anxiety-related allele is evolutionarily derived. Common/black tufted-ear marmosets and rhesus/bonnet macaques share high ecological adaptability and behavioural flexibility that we propose may be related to the maintenance of the polymorphism.

Connection Failure: Differences in White Matter Microstructure Are Associated with 5-HTTLPR but Not with Risk Seeking for Losses

S/S carriers of 5-HTTLPR have been found to be more risk seeking for losses compared to L/L carriers. This finding may be the result of reduced top-down control from the frontal cortex due to altered signal pathways involving the amygdala and ventral striatum. The serotonergic system is known to be involved in neurodevelopment and neuroplasticity. Therefore, the aim of this study was to investigate whether structural differences in white matter can explain the differences in risk-seeking behaviour. Lower structural connectivity in S/S compared to L/L carriers and a negative relationship between risk seeking for losses and connectivity were assumed. Diffusion-weighted imaging was used to compute diffusion parameters for the frontostriatal and uncinate tract in 175 genotyped individuals. The results showed no significant relationship between diffusion parameters and risk seeking for losses. Furthermore, we did not find significant differences in diffusion parameters of the S/S vs. L/L group. There were only group differences in the frontostriatal tract showing stronger structural connectivity in the S/L group, which is also reflected in the whole brain approach. Therefore, the data do not support the hypothesis that the association between 5-HTTLPR and risk seeking for losses is related to differences in white matter pathways implicated in decision-making.

Val/Met BDNF as a genetic risk for a false sense of security in post-discharge suicide risk

BACKGROUND

The time after discharge from psychiatric inpatient care is one of the most dangerous periods in terms of suicide risk. Predicting who is at higher risk could help with resource allocation to assure patients at high risk of suicide attempts are most closely followed. We previously showed that inpatients who improve their suicide ideation levels faster while in inpatient treatment are the ones with highest rates of post-discharge suicide. Here, we studied the possible genetic underpinnings associated with such risk.

METHOD

We recorded the slope of suicide ideation recovery of 710 psychiatric inpatients from which we studied two genetic variants likely associated with suicide risk: The serotonin transporter variant 5-HTTLPR, and the BDNF gene variant Val66Met.

RESULTS

We found that inpatients carrying the BDNF Met variant (hypothesized as conferring higher suicide risk) improved their suicide ideation scores faster than Val/Val carrying inpatients. No significant association was found for 5-HTTLPR.

LIMITATIONS

The present sample was genetically homogenous, and future research should replicate these findings on a more diverse sample.

CONCLUSIONS

In conclusion, we found a paradoxical result: Carrying the BDNF Met variant allows inpatients to improve faster, which was shown to confer higher risk at the post-discharge period. This may explain some inconsistencies in the literature in terms of the role of BDNF in suicide ideation and attempts.

Serotonin Transporter (SLC6A4) and FK506-Binding Protein 5 (FKBP5) Genotype and Methylation Relationships with Response to Meditation in Veterans with PTSD

Meditation-based interventions are novel and effective non-pharmacologic treatments for veterans with PTSD. We examined relationships between treatment response, early life trauma exposure, DNA polymorphisms, and methylation in the serotonin transporter (SLC6A4) and FK506-binding protein 5 (FKBP5) genes. DNA samples and clinical outcomes were examined in 72 veterans with PTSD who received meditation-based therapy in two separate studies of mindfulness-based stress reduction (MBSR) and Transcendental Meditation (TM). The PTSD Checklist was administered to assess symptoms at baseline and after 9 weeks of meditation intervention. We examined the SLC6A4 promoter (5HTTLPR_L/S insertion/deletion + rs25531_A/G) polymorphisms according to previously defined gene expression groups, and the FKBP5 variant rs1360780 previously associated with PTSD disease risk. Methylation for CpG sites of SLC6A4 (28 sites) and FKBP5 (45 sites) genes was quantified in DNA samples collected before and after treatment. The 5HTTLPR LALA high expression genotype was associated with greater symptom improvement in participants exposed to early life trauma (p = 0.015). Separately, pre to post-treatment change of DNA methylation in a group of nine FKBP5 CpG sites was associated with greater symptom improvement (OR = 2.8, 95% CI 1.1-7.1, p = 0.027). These findings build on a wealth of existing knowledge regarding epigenetic and genetic relationships with PTSD disease risk to highlight the potential importance of SLC6A4 and FKBP5 for treatment mechanisms and as biomarkers of symptom improvement.

Genetic and Phenotypic Profiling of Triptan Users in a Swedish Cluster Headache Cohort

Up to 25% of individuals who live with cluster headache (CH), an extremely painful primary headache disorder, do not adequately respond to the first-line treatment, triptans. Studies have indicated that genetic variants can play a role in treatment response. Likewise, differences in clinical characteristics can give clues to mechanisms underlying triptan non-response. Our aim was to investigate five genetic variants previously implicated in triptan response and their relation to triptan usage in our Swedish CH cohort and to investigate potential distinctions in clinical characteristics. 545 CH patients were screened for the genetic variants rs1024905, rs6724624, rs4795541, rs5443, and rs2651899 with a case control design based on triptan usage. Analysis of clinical characteristics was based on self-reported questionnaire data from 893 patients. One genetic variant, rs1024905, was significantly associated with triptan non-usage in CH (Pc = 0.010). In addition, multi-allele effector analysis showed that individuals with a higher number of effector variants were less likely to use triptans (P = 0.007). Analysis of clinical characteristics showed that triptan users were more likely to have alcohol as a trigger (57.4% vs 43.4%, P = 0.002), have autonomic symptoms (95.1% vs 88.1%, P = 0.002), and be current smokers (27.0% vs 21.9%, P = 0.033) compared to non-users. These results support the hypothesis that genetic variants can play a role in triptan usage in CH and that patients with a typical CH phenotype are more likely to use triptans.

Tailoring Type II Diabetes Treatment: Investigating the Effect of 5-HTT Polymorphisms on HbA1c Levels after Metformin Initiation

Aims

To investigate the effect of serotonin transporter (5-HTT) polymorphisms on change in HbA1c levels six months after metformin initiation in type 2 diabetes patients.

Materials and Methods

Participants of PROVALID (PROspective cohort study in patients with type 2 diabetes mellitus for VALidation of biomarkers) within the GIANTT (Groningen Initiative to ANalyse Type 2 Diabetes Treatment) cohort who initiated metformin were genotyped for combined 5-HTTLPR/rs25531 (L∗L∗, L∗S∗, and S∗S∗) and 5-HTT VNTR (STin 2.12, 12/-, and 10/-) polymorphisms, respectively. Multiple linear regression was applied to determine the change in HbA1c level from baseline date to six months across 5-HTTLPR/VNTR genotype groups, adjusted for baseline HbA1c, age, gender, triglyceride level, low-density lipoprotein level, and serum creatinine.

Results

157 participants were included, of which 56.2% were male. The average age was 59.3 ± 9.23 years, and the mean baseline HbA1c was 7.49% ± 1.21%. 5-HTTLPR was characterized in 46 patients as L∗L∗, 70 patients as L∗S∗, and 41 patients as S∗S∗ genotypes. No significant association was found between 5-HTTLPR and 5-HTT VNTR genotypes and change in HbA1c after adjustments.

Conclusions

5-HTT polymorphisms did not affect HbA1c levels six months after the start of metformin. Further long-term studies in large samples would be relevant to determine which polymorphisms can explain the variation in response to metformin treatment.

Association of 5-HTTLPR With Post-Traumatic Stress Disorder in US Service Members

Objective

Post-traumatic stress disorder (PTSD) is a mental disorder that manifests after exposure to a stressful traumatic event, such as combat experience. Accumulated evidence indicates an important genetic influence in the development of PTSD. The serotonin transporter (5-HTT) gene has been identified as a candidate for PTSD and a polymorphism of the serotonin transporter-linked promoter region (5-HTTLPR) is associated with the disorder in the general population. However, whether it is associated with PTSD in active military service members has not been investigated. This study aimed to investigate the relationship between 5-HTTLPR and PTSD in service members.

Methods

Leucocyte genomic DNA was extracted from service members, including those with PTSD (n = 134) or without PTSD (n = 639). The 5-HTTLPR polymorphism was detected by means of 2 stages of TaqMan fluorescent PCR assay. PTSD symptoms and symptom severity were assessed using the PTSD Checklist (PCL), a 17-item, DSM-based, self-report questionnaire with well-established validity and reliability. PTSD was determined based on endorsement of DSM-IV criteria and a PCL total score ≥ 44.

Results

Significant differences in biallele distribution were observed between PTSD and controls (χ2 = 7.497, P = .024). The frequency of SS, SL, and LL genotypes in the PTSD group was 0.17, 0.56, and 0.27 respectively, compared to the frequencies of 0.27, 0.43, and 0.29 in non-PTSD controls. Carriers of the L allele had higher scores for reexperiencing and arousal symptoms on the PCL, compared to SS homozygote carriers (P < .05). The triallele genotypes showed no significant differences in distribution between the PTSD and control groups (P > .05) and no relationship with PTSD symptom severity. The interaction of triallelic genotypes of 5-HTTLPR and traumatic life events was associated with re-experiencing, avoidance, and arousal (P < .05 for all). Multiple regression analysis revealed significant correlations between both biallelic and triallelic genotypes of 5-HTTLPR, the interaction of the number of stressful lifetime events, and 5-HTTLPR genotypes with PCL total score (P < .001).

Conclusion

Our findings suggested that 5-HTT might play a minor role in PTSD, and the interaction between 5-HTTLPR and the environment had effects on PCL score, complementing and emphasizing 5-HTT for PTSD, especially in the military population.

[The association of polymorphisms of the serotonin transporter gene SLC6A4 with depression]

OBJECTIVE

To study the relationship of polymorphic variants of the SLC6A4 gene with depression among people aged 25-44 years in Novosibirsk.

MATERIAL AND METHODS

Under the WHO program «MONICA-psychosocial (MOPSY)», a random representative sample of people aged 25-44 years from the population of the Oktyabrsky district of Novosibirsk (men n=725, mean age 43.4±0.4 years, response - 71.3%, women n=710, mean age 44.8±0.4 years, response - 72%). Depression was assessed using the MONICA-MOPSY psychosocial questionnaire. Every fourth respondent was examined for polymorphic variants of 5HTTLPR-VNTR SNP rs25531 A>G of the SLC6A4 gene. The study was carried out within the framework of the budget topic Reg. No. 122031700094-5.

RESULTS

The high level of depression among people aged 25-44 was 12.8% (for men 9.1%, for women - 15.92%); the average level of depression occurred in 24.5% of the population (among men in 21.24%, among women in 26.76%) (χ2=17.071, df=2, p<0.001). The most common genotype of the SLC6A4 gene, among people aged 25--4 years old in Novosibirsk, was SLA - 43.29%, LALA - 26.53% - in second place, SS - 17.87% - third, LALG - 6 genotypes were less represented genotypes. 74%, SLG - 4.18%, LGLG - 1.39%. Carrying the SLA genotype (53.3% and 63.6%) increased the chance of developing both the average level of depression by 2.359 (95% CI 1.278-4.355) times, and depression in general by 1.933 (95% CI 1.142-3.271) times, compared with persons carrying the LALA genotype (32.0% and 46.9%), (χ2=7.674, df=1, p<0.01 and χ2=6.095, df=1, p<0.05). Persons carrying the LALG genotype (54.5%) also had a higher chance of developing a mean level of depression RR=2.929 (95% CI 1.039-8.261), compared with carriers of the LALA genotype (32.0%) (χ2=4.326, df =1, p<0.05) (p<0.05).

CONCLUSION

Associative links between polymorphic variants of the SLC6A4 gene and depression have been established.

Prenatal serotonin reuptake inhibitor antidepressant exposure, SLC6A4 genetic variations, and cortisol activity in 6-year-old children of depressed mothers: A cohort study

Prenatal exposure to maternal depression and serotonin reuptake inhibitor (SRI) antidepressants both affect the development of the hypothalamic-pituitary-adrenal (HPA) system, possibly via the neurotransmitter serotonin (5HT). In a community cohort, we investigated the impact of two factors that shape prenatal 5HT signaling (prenatal SRI [pSRI] exposure and child SLC6A4 genotype) on HPA activity at age 6 years. Generalized estimating equation (GEE) models were used to study associations between cortisol reactivity, pSRI exposure, and child SLC6A4 genotype, controlling for maternal depression, child age, and sex (48 pSRI exposed, 74 nonexposed). Salivary cortisol levels were obtained at five time points during a laboratory stress challenge: arrival at the laboratory, following two sequential developmental assessments, and then 20 and 40 min following the onset of a stress-inducing cognitive/social task. Cortisol decreased from arrival across both developmental assessments, and then increased across both time points following the stress challenge in both groups. pSRI-exposed children had lower cortisol levels across all time points. In a separate GEE model, we observed a lower cortisol stress response among children with LG /S alleles compared with children with La/La alleles, and this was particularly evident among children of mothers reporting greater third trimester depressed mood. Our findings suggest that pSRI exposure and a genetic factor associated with modulating 5HT signaling shaped HPA reactivity to a laboratory stress challenge at school age.

The Neurobiological Underpinnings of Obsessive-Compulsive Symptoms in Psychosis, Translational Issues for Treatment-Resistant Schizophrenia

Almost 25% of schizophrenia patients suffer from obsessive-compulsive symptoms (OCS) considered a transdiagnostic clinical continuum. The presence of symptoms pertaining to both schizophrenia and obsessive-compulsive disorder (OCD) may complicate pharmacological treatment and could contribute to lack or poor response to the therapy. Despite the clinical relevance, no reviews have been recently published on the possible neurobiological underpinnings of this comorbidity, which is still unclear. An integrative view exploring this topic should take into account the following aspects: (i) the implication for glutamate, dopamine, and serotonin neurotransmission as demonstrated by genetic findings; (ii) the growing neuroimaging evidence of the common brain regions and dysfunctional circuits involved in both diseases; (iii) the pharmacological modulation of dopaminergic, serotoninergic, and glutamatergic systems as current therapeutic strategies in schizophrenia OCS; (iv) the recent discovery of midbrain dopamine neurons and dopamine D1- and D2-like receptors as orchestrating hubs in repetitive and psychotic behaviors; (v) the contribution of N-methyl-D-aspartate receptor subunits to both psychosis and OCD neurobiology. Finally, we discuss the potential role of the postsynaptic density as a structural and functional hub for multiple molecular signaling both in schizophrenia and OCD pathophysiology.

Insights into the molecular genetic basis of individual differences in metacognition

There is a striking lack of studies on the molecular genetic basis of metacognition, i.e., the higher-order ability to monitor mental processes. Here, an initial step toward resolving this issue was undertaken by investigating functional polymorphisms from three genes of the dopaminergic or serotonergic systems (DRD4, COMT, and 5-HTTLPR) in relation to behaviorally assessed metacognition in six paradigms across three cognitive domains. We report evidence for a task-dependent higher average confidence level (metacognitive bias) in carriers of at least one S or L_G-allele in the 5-HTTLPR genotype and integrate these findings within a differential susceptibility framework.

Peripheral control of psychiatric disorders: Focus on OCD. Are we there yet?

"We are all in this together" - we often hear this phrase when we want to flag up a problem that is not for a single individual but concerns us all. A similar reflection has been recently made in the field of mental disorders where brain-centric scientists have started to zoom out their brain-focused graphical representations of the mechanisms regulating psychiatric diseases to include other organs or mediators that did not belong historically to the world of neuroscience. The brain itself - that has long been seen as a master in command secluded in its fortress (the blood brain barrier), has now become a collection of Airbnb(s) where all sorts of cells come in and out and sometimes even rearrange the furniture! Under this new framework of reference, mental disorders have become multisystem pathologies where different biological systems - not just the CNS -contribute 'all together' to the development and severity of the disease. In this narrative review article, we will focus on one of the most popular biological systems that has been shown to influence the functioning of the CNS: the immune system. We will specifically highlight the two main features of the immune system and the CNS that we think are important in the context of mental disorders: plasticity and memory.

Ectopic expression of MmSERT, a mouse serotonin transporter gene, regulates salt tolerance and ABA sensitivity in apple and Arabidopsis

5-hydroxytryptamine (5-HT) is ubiquitously present in animals and plants, playing a vital regulatory role. SERT, a conserved serotonin reuptake transporter in animals, regulates intracellular and extracellular concentrations of 5-HT. Few studies have reported 5-HT transporters in plants. Hence, we cloned MmSERT, a serotonin reuptake transporter, from Mus musculus. Ectopic expression of MmSERT into apple calli, apple roots and Arabidopsis. Because 5-HT plays a momentous role in plant stress tolerance, we used MmSERT transgenic materials for stress treatment. We found that MmSERT transgenic materials, including apple calli, apple roots and Arabidopsis, exhibited a stronger salt tolerance phenotype. The reactive oxygen species (ROS) produced were significantly lower in MmSERT transgenic materials compared with controls under salt stress. Meanwhile, MmSERT induced the expression of SOS1, SOS3, NHX1, LEA5 and LTP1 in response to salt stress. 5-HT is the precursor of melatonin, which regulates plant growth under adversity and effectively scavenges ROS. Detection of MmSERT transgenic apple calli and Arabidopsis revealed higher melatonin levels than controls. Besides, MmSERT decreased the sensitivity of apple calli and Arabidopsis to abscisic acid (ABA). In summary, these results demonstrated that MmSERT plays a vital role in plant stress resistances, which perhaps serves as a reference for the application of transgenic technology to improve crops in the future.

The Role of Genetics in the Development and Pharmacotherapy of Depression and Its Impact on Drug Discovery

Complex disorders, such as depression, remain a mystery for scientists. Although genetic factors are considered important for the prediction of one's vulnerability, it is hard to estimate the exact risk for a patient to develop depression, based only on one category of vulnerability criteria. Genetic factors also regulate drug metabolism, and when they are identified in a specific combination, may result in increased drug resistance. A proper understanding of the genetic basis of depression assists in the development of novel promising medications and effective disorder management schemes. This review aims to analyze the recent literature focusing on the correlation between specific genes and the occurrence of depression. Moreover, certain aspects targeting a high drug resistance identified among patients suffering from major depressive disorder were highlighted in this manuscript. An expected direction of future drug discovery campaigns was also discussed.

COMT but Not 5HTTLPR Gene Is Associated with Depression in First-Episode Psychosis: The Role of Stressful Life Events

Serotonergic and dopaminergic systems are involved in the regulation of mood and reactivity to psychological stress. This study explores, in a sample of first episode psychosis (FEP) patients, whether more severe depressive symptoms were found in those who: (1) experienced a major stressful event in the 6 months preceding illness onset; and (2) were homozygous for the COMT Val158 allele or carrying the S allele of 5-HTTLPR. A total of 186 FEP patients recruited were assessed using the Hamilton Rating Scale for Depression (HAMD) for depressive symptoms. Stressful life events (SLEs) were collected by the List of Events Scale. The genotypes of 5-HTTLPR, rs25531, and COMT Val158 Met were performed. It has been found that higher levels of depression is associated with the presence of SLEs (p = 0.019) and with COMT Val158 allele homozygosity (p = 0.029), but not with carrying the S allele of 5-HTTLPR. The COMT gene moderates the association between depression and SLEs as Val158 allele homozygote patients experiencing SLEs had the highest level of depressive symptoms compared to the others (p = 0.002). The present study provides initial evidence for an effect of the COMT Val158 homozygosity and severe stressful life events on the severity of depressive symptoms in first episode psychosis.

Psychotherapies and digital interventions for OCD in adults: What do we know, what do we need still to explore?

BACKGROUND

Despite significant advances in the understanding and treatment of obsessive compulsive disorder (OCD), current treatment options are limited in terms of efficacy for symptom remission. Thus, assessing the potential role of iterative or alternate psychotherapies is important. Also, the potential role of digital technologies to enhance the accessibility of these therapies, should not be underestimated. We also need to embrace the idea of a more personalized treatment choice, being cognisant of clinical, genetic and neuroimaging predictors of treatment response.

PROCEDURES

Non-systematic review of current literature on emerging psychological and digital therapies for OCD, as well as of potential biomarkers of treatment response.

FINDINGS

A number of 'third wave' therapies (e.g., Acceptance and Commitment Therapy, Mindfulness-Based Cognitive Therapy) have an emerging and encouraging evidence base in OCD. Other approaches entail employment of elements of other psychotherapies such as Dialectical Behaviour Therapy; or trauma-focussed therapies such as Eye Movement Desensitisation and Reprocessing, and Imagery Rescripting and Narrative Therapy. Further strategies include Danger Ideation Reduction Therapy and Habit Reversal. For these latter approaches, large-scale randomised controlled trials are largely lacking, and the precise role of these therapies in treating people with OCD, remains to be clarified. A concentrated 4-day program (the Bergen program) has shown promising short- and long-term results. Exercise, music, and art therapy have not been adequately tested in people with OCD, but may have an adjunctive role. Digital technologies are being actively investigated for enhancing reach and efficacy of psychological therapies for OCD. Biomarkers, including genetic and neuroimaging, are starting to point to a future with more 'personalised medicine informed' treatment strategizing for OCD.

CONCLUSIONS

There are a number of potential psychological options for the treatment of people with OCD who do not respond adequately to exposure/response prevention or cognitive behaviour therapy. Adjunctive exercise, music, and art therapy might be useful, albeit the evidence base for these is very small. Consideration should be given to different ways of delivering such interventions, including group-based, concentrated, inpatient, or with outreach, where appropriate. Digital technologies are an emerging field with a number of potential applications for aiding the treatment of OCD. Biomarkers for treatment response determination have much potential capacity and deserve further empirical testing.

Parental rejection in early adolescence predicts a persistent ADHD symptom trajectory across adolescence

Despite a general decrease of attention-deficit/hyperactivity disorder (ADHD) symptoms during adolescence, these may persist in some individuals but not in others. Prior cross-sectional studies have shown that parenting style and their interaction with candidate genes are associated with ADHD symptoms. However, there is a lack of longitudinal research examining the independent and interactive effects of parenting and plasticity genes in predicting the course of attention-deficit/hyperactivity disorder (ADHD) symptoms across adolescence. Here, we investigated how children perceived their parents' parenting style (i.e., rejection, overprotection, and emotional warmth) at the age of 11, and their interaction with DRD4, MAOA, and 5-HTTLPR genotypes on parent-reported ADHD symptoms at three time points (mean ages 11.1, 13.4, and 16.2 years) in 1730 adolescents from the TRacking Adolescents' Individual Lives Survey (TRAILS). Growth Mixture Modeling in Mplus identified four ADHD symptom trajectories: low, moderate stable, high decreasing, and high persistent. Perceived parental rejection predicted class membership in the high persistent trajectory compared to the other classes (p < 0.001, odds ratios between 2.14 and 3.74). Gene-environment interactions were not significantly related to class membership. Our results indicate a role of perceived parental rejection in the persistence of ADHD symptoms. Perceived parental rejection should, therefore, be taken into consideration during prevention and treatment of ADHD in young adolescents.

Prevalence of Common Alleles of Some Stress Resilience Genes among Adolescents Born in Different Periods Relative to the Socioeconomic Crisis of the 1990s in Russia

Social stress is common among people and is considered one of the causes of the declining birth rate. Predisposition to stress and stress-induced disorders is largely determined genetically. We hypothesized that due to differences in stress resistance, carriers of different genetic variants of genes associated with stress resilience and stress-induced diseases may have dissimilar numbers of offspring under conditions of long-term social stress. To test this hypothesis, a comparative analysis of frequencies of seven common polymorphic regions [exon 3 variable number of tandem repeats (VNTR) of the DRD4 gene, rs4680 of COMT, STin2 VNTR and the 5-HTTLPR (rs774676466) insertion/deletion polymorphism of SLC6A4, rs4570625 of TPH2, rs6265 of BDNF, and rs258747 of NR3C1] was performed on standardized groups of randomly selected adolescents born before, during, and after severe socioeconomic deprivation (the crisis of the 1990s in Russia). There were significant differences in frequencies of "long" alleles of the DRD4 gene (p = 0.020, χ² = 5.492) and rs4680 (p = 0.022, χ² = 5.289) in the "crisis" group as compared to the combined "noncrisis" population. It is possible that the dopaminergic system had an impact on the successful adaptation of a person to social stress.

Methylation of the serotonin reuptake transporter gene and non-motor symptoms in dystonia patients

BACKGROUND

Dystonia is a rare movement disorder, in which patients suffer from involuntary twisting movements or abnormal posturing. Next to these motor symptoms, patients have a high prevalence of psychiatric comorbidity, suggesting a role for serotonin in its pathophysiology. This study investigates the percentage of DNA methylation of the gene encoding for the serotonin reuptake transporter (SLC6A4) in dystonia patients and the associations between methylation levels and presence and severity of psychiatric symptoms.

METHODS

Patients with cervical dystonia (n = 49), myoclonus dystonia (n = 41) and dopa-responsive dystonia (DRD) (n = 27) and a group of healthy controls (n = 56) were included. Psychiatric comorbidity was evaluated with validated questionnaires. Methylation levels of 20 CpG sites situated 69 to 213 base pairs upstream of the start codon of SLC6A4 were investigated. Methylation in dystonia patients was compared to healthy controls, correcting for age, and correlated with psychiatric comorbidity.

RESULTS

Bootstrapped quantile regression analysis showed that being a dystonia patient compared to a healthy control significantly explains the methylation level at two CpG sites (CpG 24: pseudo-R² = 0.05, p = 0.04, CpG 32: pseudo-R² = 0.14, p = 0.03). Subgroup analysis revealed that being a DRD patient significantly explained a part of the variance of methylation levels at two CpG sites (CpG 21: pseudo-R² = 0.03, p = 0.00, CpG 24: pseudo-R² = 0.06, p = 0.03). Regression analysis showed that methylation level at CpG 38 significantly explained a small proportion of the variance of severity score for anxiety (R² = 0.07, p = 0.04) and having a diagnosis of depression (Nagelkerke R²: 0.11, p = 0.00). Genotype of the 5-HTTLPR polymorphism had no additional effect on these associations.

CONCLUSIONS

This study showed an association between percentage of methylation at several specific sites of the promoter region of SLCA64 and (dopa-responsive) dystonia patients compared to healthy controls. Furthermore, methylation levels were associated with severity of anxiety and presence of a depressive disorder in the dystonia group. This study suggests alterations in the serotonergic metabolism in dystonia patients, and its relation with the non-motor symptoms.

Molecular genetic associations between a prominent serotonin transporter gene polymorphism (5-HTTLPR/rs25531) and individual differences in tendencies toward autistic traits and generalized internet use disorder in China and Germany

BACKGROUND

The serotonin transporter polymorphism 5-HTTLPR is an extensively investigated genetic marker of autistic traits or autism spectrum disorder, and recently has also been studied in the realm of internet use disorder (IUD), yet the findings remain controversial. Therefore, the present study aimed to explore associations between 5-HTTLPR (also including SNP rs25531) and autistic traits/IUD tendencies and to assess whether the relationship between autistic traits and IUD tendencies varies by this genetic marker in participants from China and Germany.

METHODS

A total of 540 Chinese and 563 German subjects were genotyped for 5-HTTLPR/rs25531 and completed the Adult Autism Spectrum Quotient questionnaire and the short version of the Internet Addiction Test.

RESULTS

Carriers of the low expressing S'S' genotype (S, L_G ) showed significantly higher levels of autistic traits than the high expressing allele (e.g. L_A ) carriers in both samples. There was no significant effect of 5-HTTLPR/rs25531 on IUD either in the Chinese or Germany samples, whereas positive correlations between autistic traits and IUD varied by 5-HTTLPR/rs25531 genotypes and also differed between Chinese and German samples. In the Chinese sample, positive correlations were mainly driven by S'S' and S'L' carriers, while they were mainly determined by S'L' and L'L' carriers in the German sample. Further analyses revealed that the associations between autistic traits and IUD tended in parts to be more strongly pronounced in the complete German sample compared to the complete Chinese sample, and also varied depending on 5-HTTLPR/rs25531 genotypes (in S'S' carriers: China > Germany; in S'L' and L'L' carriers: China < Germany; both in terms of more positive associations).

CONCLUSIONS

Our findings suggest carriers of low expressing alleles (S, L_G ) are more likely to show higher autistic traits in both Chinese and German samples. Furthermore, the present work shows that both 5-HTTLPR/rs25531 and cultural differences might be of relevance to understand associations between autistic traits and IUD tendencies, but this needs to be further backed up.

Genetic associations with resilience to potentially traumatic events and vantage sensitivity to social support

INTRODUCTION

Stress responses and mental health outcomes greatly vary when individuals are exposed to potentially traumatic events (PTEs). The Differential Susceptibility Model (DSM) (Pluess, 2015) suggests individual differences in stress responses are influenced by gene-environment interactions, with genes conferring reactivity. While individuals can be resilient (or vulnerable) to PTEs, they can also have vantage sensitivity (or resistance) to social support. This study examined whether selected genotypes moderated the effect of PTEs and social support on mental health.

METHODS

This cross-sectional candidate gene study included 450 college students (M age = 20.4, 79.3 % women) who provided buccal cells for genotyping and completed measures of psychosocial variables. DNA was genotyped for 12 genetic variants.

RESULTS

Hierarchical regression revealed that the Mental Health Inventory (MHI) was associated with the Trauma History Questionnaire (THQ), rs1800795 in IL-6, and THQ × rs1800795 [R² = 0.10, F(3, 418) = 15.68, p < .01]. The MHI was associated with the Social Support Survey (SSS), rs4680 in COMT, and SSS × rs4680 [R² = 0.24, F(3, 429) = 44.19, p < .01]. Only THQ and SSS survived multiple testing corrections.

DISCUSSION

Findings partially support the DSM that the G/G genotype of rs1800795 in IL-6 is associated with resilience to PTEs, and the Met/Met genotype of rs4680 in COMT is associated with vantage sensitivity to social support. Limitations include cross-sectional design, limited PTE measurement, small convenience sample, and noncorrection for multiple significance test. Clinicians need to view resilience holistically and understand resilience is associated with psychosocial and genetic factors.

Genetically predicted circulating levels of glycine, glutamate, and serotonin in relation to the risks of three major neurodegenerative diseases: A Mendelian randomization analysis

It has been previously postulated that blood neurotransmitters might affect risks of neurodegenerative diseases. Here, a Mendelian Randomization (MR) study was conducted to explore whether genetically predicted concentrations of glycine, glutamate and serotonin were associated with risks of Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). From three genome-wide association studies of European ancestry, single nucleotide polymorphisms strongly associated with glycine, glutamate and serotonin were selected as genetic instrumental variables. Corresponding summary statistics were also obtained from the latest genome-wide association meta-analyses of AD, PD and ALS. The inverse-variance weighted MR and multiple sensitivity analyses were performed to evaluate causal effects of genetically predicted levels of neurotransmitters on risks of neurodegenerative diseases. The statistical significance threshold was set at P < 0.0056 using the Bonferroni-correction, while 0.0056 < P < 0.05 was considered suggestive evidence for a causal association. There was a causal association of elevated blood glutamate levels with higher AD risks. The odds ratio (OR) of AD was 1.311 [95% confidence interval (CI), 1.087-1.580; P = 0.004] per one standard deviation increase in genetically predicted glutamate concentrations. There was suggestive evidence in support of a protective effect of blood serotonin on AD (OR = 0.607; 95% CI, 0.396-0.932; P = 0.022). Genetically predicted glycine levels were not associated with the risk of AD (OR = 1.145; 95% CI, 0.939-1.396; P = 0.180). Besides, MR analyses indicated no causal roles of three blood neurotransmitters in PD or ALS. In conclusion, the MR study provided evidence supporting the association of elevated blood glutamate levels with higher AD risks and the association of increased blood serotonin levels with lower AD risks. Triangulating evidence across further study designs is still warranted to elucidate the role of blood neurotransmitters in risks of neurodegenerative diseases.

In silico analysis of a SLC6A4 G100V mutation in lung cancers

SLC6A4 is a serotonin re-uptake transporter which has been a target for anti-depressant therapies but recently some mutations have been described in cancer cells. Here, we characterize mutations in SLC6A4 that appear in cancer cells. We employed several validated computational and artificial intelligence algorithms to characterize the mutations. We identified a previously uncharacterized G100V mutation in lung cancers. In sillico structural analysis reveals that this mutation may affect SLC6A4 ligand binding and subsequently its function. We also identified several other mutations that may affect the structure of the protein. This preliminary analysis highlights the role of SLC6A4 in human cancers.

The regulatory role of AP-2β in monoaminergic neurotransmitter systems: insights on its signalling pathway, linked disorders and theragnostic potential

Monoaminergic neurotransmitter systems play a central role in neuronal function and behaviour. Dysregulation of these systems gives rise to neuropsychiatric and neurodegenerative disorders with high prevalence and societal burden, collectively termed monoamine neurotransmitter disorders (MNDs). Despite extensive research, the transcriptional regulation of monoaminergic neurotransmitter systems is not fully explored. Interestingly, certain drugs that act on these systems have been shown to modulate central levels of the transcription factor AP-2 beta (AP-2β, gene: TFAP2Β). AP-2β regulates multiple key genes within these systems and thereby its levels correlate with monoamine neurotransmitters measures; yet, its signalling pathways are not well understood. Moreover, although dysregulation of TFAP2Β has been associated with MNDs, the underlying mechanisms for these associations remain elusive. In this context, this review addresses AP-2β, considering its basic structural aspects, regulation and signalling pathways in the controlling of monoaminergic neurotransmitter systems, and possible mechanisms underpinning associated MNDS. It also underscores the significance of AP-2β as a potential diagnostic biomarker and its potential and limitations as a therapeutic target for specific MNDs as well as possible pharmaceutical interventions for targeting it. In essence, this review emphasizes the role of AP-2β as a key regulator of the monoaminergic neurotransmitter systems and its importance for understanding the pathogenesis and improving the management of MNDs.

Emotional self-regulation, impulsivity, 5-HTTLPR and tobacco use behavior among psychiatric inpatients

BACKGROUND

While the serotonin transporter (SLC6A4) gene, 5-HTTLPR, interacts with the social environment to influence both emotional self-regulation and smoking behavior, less is known about interactions between emotional self-regulation and 5-HTTLPR or their joint influence on tobacco use. Here, we examined such interactions among psychiatric inpatients, the population with the highest rates of smoking.

METHODS

Participants (506 adults) were psychiatric inpatients at The Menninger Clinic in Houston TX between 2012 and 16. Most were white (89%), male (55%), with a mean age of 32.3 years. Participants completed the Difficulties in Emotional Regulation Scale (DERS) at admission. We examined interactions with smoking among three DERS subscales and 5-HTTLPR, controlling for sex, race and age.

RESULTS

Smoking rates were higher among those with the 5-HTTPLR L'L' genotype compared to peers carrying an S' allele (47.9% vs. 37.4%, respectively). Among S' allele carrying participants, impulse control difficulties (OR = 1.09; 95%CI: 1.03-1.14) and lack of emotion clarity (OR = 1.06; 95%CI: 1.00-1.11) increased risk for ever using tobacco, while accessing more ways to regulate emotion (OR = 0.95; 95%CI: 0.92-0.99) offered a protective effect against ever using tobacco. Neither demographic nor DERS covariates were associated with using tobacco among the L'L' group.

LIMITATIONS

This ethnically homogenous sample limits generalizability and using a binary outcome can over-estimate a gene environment interaction effect.

CONCLUSIONS

Emotional self-regulation exerts a stronger influence on using tobacco among carriers of an S' allele of 5-HTTLPR than peers with the L'L' genotype. Promoting emotional self-regulatory skills may have benefits for preventing tobacco use.

Correlation between 5-HTTLPR gene polymorphism and cognitive function of traumatic stress in Chinese Han children

BACKGROUND

Post-traumatic stress disorder (PTSD) is a trauma-related psychological disorder with serious social and familial impacts. The involvement of 5-hydroxytryptamine transporter gene-linked polymorphic region (5-HTTLPR) in numerous mental disorders has been documented. This study explored the correlation between 5-HTTLPR gene polymorphism and cognitive function in Chinese Han children with PTSD.

METHODS

A total of 60 PTSD children treated from December 2019 to December 2021 were selected as study participants, with another 60 healthy children selected as controls. We assessed the cognitive function of participants using the Mini-Mental State Examination (MMSE). Additionally, the PTSD level was estimated by the Children's Revised Impact of Event Scale (CRIES). The 5-HTTLPR gene polymorphism was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The genotype and allele frequency were evaluated via case-control association analysis.

RESULTS

Children in the PTSD group showed low MMSE scores and high CRIES scores. In terms of genotype, cases of LL, LS, and SS in PTSD children were 4 (6.67%), 20 (33.3%), and 36 (60.00%), and 18 (30.00%), 28 (46.67%), and 14 (23.33%) cases in healthy controls. In terms of allele gene frequency, incidences of L and S were 23.33% and 76.67% in PTSD children, respectively, and were 53.33% and 46.67% in healthy controls, respectively. Moreover, the CRIES and MMSE scores of LS and SS genotypes were evidently different from those of LL genotype in PTSD children.

CONCLUSIONS

Polymorphism of the 5-HTTLPR gene is correlated with cognitive dysfunction in Chinese Han children with PTSD.

Identification of Functional Single Nucleotide Polymorphisms in the Porcine SLC6A4 Gene Associated with Aggressive Behavior in Weaned Pigs after Mixing

Variation in genes of the serotonergic system influence aggressive behavior by affecting serotonin levels in the central and cortical nervous system. SLC6A4 (serotonin transporter) is a master regulator of 5-HT signaling and involved in the regulation of aggressive behavior in humans and rodents. To identify potential functional single nucleotide polymorphisms (SNPs) for the porcine SLC6A4 gene associated with aggressive behavior, a total of 500 pigs (268 barrows and 232 gilts) were selected and mixed in 51 pens. Their behavior was recorded and observed for 72 h after mixing. Based on a composite aggressive score (CAS), the most aggressive and the least aggressive pigs within each pen were selected separately (a total of 204 pigs). Ear tissue was sampled to extract genomic DNA. Eight SNPs in the 5'-flanking region, coding region, and 3'-untranslated region (3'-UTR) of SLC6A4 were genotyped, of which 6 SNPs had significant differences (P < 0.05) in allele frequency between the most aggressive and least aggressive pigs. Luciferase activity was greater in plasmids of genotype GG than plasmids of genotype CC of rs345058216 (P < 0.01). Computational analysis nominated MAZ as putative transcription factor (TF) with higher probability to bind the SLC6A4 promoter at the SNP (rs345058216) site. Also, we demonstrated that MAZ overexpression modulates SLC6A4 promoter activity in allele-specific manner with an in vitro assay. In addition, we demonstrated that SLC6A4 was a direct target of miR-671-5p. The dual luciferase reporter gene assay and cell transfection were performed to examine the role of miR-671-5p in regulating SLC6A4 expression. The luciferase assays revealed that the SNP rs332335871 affects regulation of miR-671-5p in SLC6A4 expression. After overexpression of miR-671-5p in porcine primary neural cells, the SLC6A4 mRNA levels can be significantly reduced. In conclusion, we here found that miR-671-5p and MAZ mediated porcine SLC6A4 expression level, which provides the possible molecular mechanism of aggressive behavior.

Novel GxE effects and resilience: A case:control longitudinal study of psychosocial stress with war-affected youth

Responses to early life adversity differ greatly across individuals. Elucidating which factors underlie this variation can help us better understand how to improve health trajectories. Here we used a case:control study of refugee and non-refugee youth, differentially exposed to war-related trauma, to investigate the effects of genetics and psychosocial environment on response to trauma. We investigated genetic variants in two genes (serotonin transporter, 5-HTT, and catechol-O-methyltransferase, COMT) that have been implicated in response to trauma. We collected buccal samples and survey data from 417 Syrian refugee and 306 Jordanian non-refugee youth who were enrolled in a randomized controlled trial to evaluate a mental health-focused intervention. Measures of lifetime trauma exposure, resilience, and six mental health and psychosocial stress outcomes were collected at three time points: baseline, ~13 weeks, and ~48 weeks. We used multilevel models to identify gene x environment (GxE) interactions and direct effects of the genetic variants in association with the six outcome measures over time. We did not identify any interactions with trauma exposure, but we did identify GxE interactions with both genes and resilience; 1) individuals with high expression (HE) variants of 5-HTTLPR and high levels of resilience had the lowest levels of perceived stress and 2) individuals homozygous for the Val variant of COMT with high levels of resilience showed stable levels of post-traumatic stress symptoms. We also identified a direct protective effect of 5-HTTLPR HE homozygotes on perceived insecurity. Our results point to novel interactions between the protective effects of genetic variants and resilience, lending support to ideas of differential susceptibility and altered stress reactivity in a cohort of war-affected adolescents.

Association study of Catechol-O-Methyltransferase (COMT) rs4680 Val158Met gene polymorphism and suicide attempt in Mexican adolescents with major depressive disorder

AIM

We analyzed the association between SLC6A4, DRD2, COMT and MAOA genes and suicide attempt (SA) in Mexican adolescent patients with major depressive disorder (MDD).

METHODS

The sample included 197 adolescents (127 females and 70 males) with principal diagnosis of MDD. Among them, 63 patients had SA at least once and 134 had not SA. The mean age of patients with and without SA was 15 ± 1.4 and 14 ± 1.5 years, respectively. We analyzed the genotype and allele distribution between patients with and without SA of SLC6A4 (5HTTLPR/rs25531), DRD2 (rs6275), COMT (rs4680), and MAOA (uVNTR).

RESULTS

We did not find genotype or allele association between SA and SLC6A4 (χ²=0.67, p = 0.71; χ²=0.07, p = 0.77, respectively), DRD2 (χ²=0.05, p = 0.97; χ²=0.003, p = 0.95), and MAOA (females: χ²=0.86, p = 0.64; χ²=0, p = 1/males: χ²=0.008, p = 0.92) genes. However, there were differences in genotype frequencies of COMT/rs4680 between patients with SA and without SA (χ²=11.17, p = 0.003). Also, we observed a high frequency of Met158 allele showing an increased risk of having presented at least one SA (χ²=10.6, p = 0.001; OR = 1.43; 95% CI, 1.17-1.74).

CONCLUSIONS

Our findings showed an association between low activity genotype and allele of Val158Met polymorphism of COMT gene and SA in Mexican adolescents with MDD.

Genetics of social anxiety disorder: a systematic review

Social anxiety disorder (SAD) is a common psychiatric disorder, often associated with avoidant temperament. Research studies have implicated a strong genetic architecture of SAD. We have conducted a systematic review on the genetics of SAD and yielded 66 articles. In general, prior research studies have focused on the serotonin transporter, oxytocin receptor, brain-derived neurotrophic factor and catechol-O-methyltransferase genes. Mixed and inconsistent results have been reported. Additional approaches and phenotypes have also been investigated, including pharmacogenetics of treatment response, imaging genetics and gene-environment interactions. Future directions warrant further international collaborative efforts, deep-phenotyping of clinical characteristics including consistent and reliable measurement-based symptom severity, and larger sample sizes to ensure sufficient power for stratification due to the heterogeneity of this chronic and often debilitating condition.

Methylation of the serotonin transporter gene moderates the depressive subjective effect of cocaine

Genetic variation in the serotonin transporter (SLC6A4) has been shown to moderate the acute subjective effects of cocaine. Methylation of the SLC6A4 gene is associated with decreased transcription of the serotonin transporter, leading to increased serotonin in the synapse. In this study, methylation of the SLC6A4 gene was investigated in the moderation of the subjective effects of cocaine. Non-treatment-seeking cocaine-dependent individuals (N = 53) were intravenously administered cocaine (40 mg) and saline in a randomized order. The subjective effects of cocaine were self-reported using a visual analog scale starting prior to the administration of cocaine (-15 min) or saline and up to 20 min after infusion. Participants were evaluated for methylation of the SLC6A4 promoter region and 5-HTTLPR genotype. A series of ANCOVAs for SLC6A4 methylation (high/low) were run for each of ten subjective and three cardiovascular effects controlling for age, sex [utilizing the sex-determining region Y protein (SRY)], and population structure (determined from ancestry informative markers and STRUCTURE software). Participants with SLC6A4 hypermethylation reported greater subjective response to cocaine for 'depressed' relative to participants with SLC6A4 hypomethylation (experiment-wise p = 0.002). These findings indicate that SLC6A4 methylation moderates the 'depressed' subjective effect of cocaine in non-treatment-seeking cocaine-dependent participants.

Influence of 5-HTTLPR polymorphism on postpartum depressive and posttraumatic symptoms

INTRODUCTION

Postpartum depression (PPD) is a multifactor disorder caused by psychological, social, and also biological factors. 5-HTTLPR polymorphism in the promoter region of serotonin transporter gene seems to influence PPD onset. In this study, we examined the effect of 5-HTTLPR polymorphism on prenatal and postnatal symptoms of depression and posttraumatic stress in women.

METHODS

A longitudinal design with three points - time 1 (32-40 weeks gestation); time 2 (2 or 3 weeks after birth), and time 3 (3 months after birth) - was made. A total of 141 women were recruited during childbirth preparation courses. At time 1, women completed the Beck Depression Inventory (BDI) and the Los Angeles Symptoms Checklist (LASC). At time 2, they fulfilled BDI and Edinburgh Postnatal Depression Scale (EDPS), LASC and the Perinatal Posttraumatic stress disorder (PTSD) Questionnaire (PPQ); midwives and nurses collected biological test tubes by blood sampling for the genetic analysis. At time 3, the women were reassessed for BDI, LASC, EDPS, and PPQs. Analysis of variance and moderation analysis were used to correlate genotype and psychological investigations.

RESULTS

Results showed that, compared with LL/LS genotypes, SS genotype moderated cognitive depressive symptoms onset at T2 and T3. Moreover, this genotype correlated, directly or indirectly, with PTSD postpartum aspects (re-experience, avoidance, and hyperarousal).

DISCUSSION

Findings revealed that a lower expression of serotonin transporter gene, associated with SS genotype, seems to render women more vulnerable to depressive and PTSD symptoms after childbirth.

Serotonin transporter functional polymorphisms potentially increase risk of schizophrenia separately and as a haplotype

Schizophrenia is a severe, disabling psychiatric disorder with unclear etiology. Family-based, twins, and adoption studies have shown that genetic factors have major contributions in schizophrenia occurrence. Until now, many studies have discovered the association of schizophrenia and its comorbid symptoms with functional polymorphisms that lie within serotonin reuptake pathway genes. Here, we aimed to investigate the association of three variable number tandem repeats (VNTR) functional polymorphisms in MAOA and SLC6A4 with schizophrenia in the Iranian population. Two hundred and forty-one subjects with schizophrenia and three hundred and seventy age and sex-matched healthy controls were genotyped for MAOA promoter uVNTR, 5-HTTLPR, and STin2 polymorphisms. Genotyping was performed by polymerase chain reaction (PCR) with locus-specific primers and running the PCR product on agarose 2.5% gel electrophoresis. Finally, the statistical inference was performed using R programming language and Haploview software. MAOA promoter uVNTR analysis of allele frequency showed no differences between schizophrenia subjects and healthy controls in both males and females and no significant differences were observed between female cases and female controls in MAOA promoter uVNTR 4 repeat frequency. Also, there were no differences between Schizophrenia and healthy control groups in 5-HTTLPR allele and genotype frequency but, 5-HTTLPR S allele carriers are significantly more frequent among cases. In addition, STin2.12 repeats were significantly more frequent among schizophrenia patients. Genotype comparison suggested that 5-HTTLPR S allele and STin2.12 repeat carriers were significantly more frequent among schizophrenia cases and being STin2.12 repeat carrier significantly increase the risk of schizophrenia occurrence. Besides, analysis of haplotype showed stronger linkage disequilibrium between 5-HTTLPR and STin2 haplotype block in cases than controls. These results suggest that SLC6A4 functional polymorphisms potentially could play a possible role as risk factors for the incidence of schizophrenia.

Current Understanding of the Genetics of Tourette Syndrome

Gilles de la Tourette syndrome (TS) is a common, childhood-onset psychiatric disorder characterized by persistent motor and vocal tics. It is a heterogeneous disorder in which the phenotypic expression may be affected by environmental factors, such as immune responses. Furthermore, several studies have shown that genetic factors play a vital role in the etiology of TS, as well as its comorbidity with other disorders, including attention deficit hyperactivity disorder, obsessive-compulsive disorder, and autism spectrum disorder. TS has a complex inheritance pattern and, according to various genetic studies, several genes and loci have been correlated with TS. Genome-wide linkage studies have identified Slit and Trk-like 1 (SLITRK1) and histidine decarboxylase (HDC) genes, and candidate gene association studies have extensively investigated the dopamine and serotonin system genes, but there have been no consistent results. Moreover, genome-wide association studies have implicated several genetic loci; however, larger study cohorts are needed to confirm this. Copy number variations, which are polymorphisms in the number of gene copies due to chromosomal deletions or duplications, are considered another significant source of mutations in TS. In the last decade, whole genome/exome sequencing has identified several novel genetic mutations in patients with TS. In conclusion, more studies are needed to reveal the exact mechanisms of underlying TS, which may help to provide more information on the prognosis and therapeutic plans for TS.

Genetic Variants Associated With Resilience in Human and Animal Studies

Resilience is broadly defined as the ability to maintain or regain functioning in the face of adversity and is influenced by both environmental and genetic factors. The identification of specific genetic factors and their biological pathways underpinning resilient functioning can help in the identification of common key factors, but heterogeneities in the operationalisation of resilience have hampered advances. We conducted a systematic review of genetic variants associated with resilience to enable the identification of general resilience mechanisms. We adopted broad inclusion criteria for the definition of resilience to capture both human and animal model studies, which use a wide range of resilience definitions and measure very different outcomes. Analyzing 158 studies, we found 71 candidate genes associated with resilience. OPRM1 (Opioid receptor mu 1), NPY (neuropeptide Y), CACNA1C (calcium voltage-gated channel subunit alpha1 C), DCC (deleted in colorectal carcinoma), and FKBP5 (FKBP prolyl isomerase 5) had both animal and human variants associated with resilience, supporting the idea of shared biological pathways. Further, for OPRM1, OXTR (oxytocin receptor), CRHR1 (corticotropin-releasing hormone receptor 1), COMT (catechol-O-methyltransferase), BDNF (brain-derived neurotrophic factor), APOE (apolipoprotein E), and SLC6A4 (solute carrier family 6 member 4), the same allele was associated with resilience across divergent resilience definitions, which suggests these genes may therefore provide a starting point for further research examining commonality in resilience pathways.

Pharmacogenetics of Addiction Therapy

Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies with response to treatment based on individual genetic makeup. In this chapter, we will discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The continued elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.

OGDHL Variant rs2293239: A Potential Genetic Driver of Chinese Familial Depressive Disorder

Depressive disorders are a severe psychiatric and social problem that affect more than 4% of the global population. Depressive disorders have explicit hereditary characteristics; however, the precise driving genetic force behind these disorders has not yet been clearly illustrated. In the present study, we recruited a three-generation Chinese pedigree in which 5 of 17 members had long-term depression. We conducted whole-exome sequencing to identify the genetic mutation profiles of the family, and a list of susceptible genetic variations that were highly associated with depression onset was revealed via multiple omics analysis. In particular, a non-synonymous single nucleotide variation in the oxoglutarate dehydrogenase-like (OGDHL) gene, rs2293239 (p.Asn725Ser), was identified as one of the major driving genetic forces for depression onset in the family. This variant causes an important conformational change in the transketolase domain of OGDHL, thus reducing its binding affinity with the cofactor thiamine pyrophosphate and eventually resulting in the abnormal accumulation of glutamate in the brain. Brain imaging analysis further linked the rs2293239 variant with an enlarged amygdala and cerebellum in depressive family members. In summary, the present study enhances the current genetic understanding of depressive disorders. It also provides new options for prioritizing better clinical therapeutic regimens, as well as identifying a new protein target for the design of highly specific drugs to treat depressive disorders.

Serotonin Transporter Genetic Variation and Antidepressant Response and Tolerability: A Systematic Review and Meta-Analysis

Antidepressants are used to treat several psychiatric disorders; however, a large proportion of patients do not respond to their first antidepressant therapy and often experience adverse drug reactions (ADR). A common insertion–deletion polymorphism in the promoter region (5-HTTLPR) of the serotonin transporter (SLC6A4) gene has been frequently investigated for its association with antidepressant outcomes. Here, we performed a systematic review and meta-analysis to assess 5-HTTLPR associations with antidepressants: (1) response in psychiatric disorders other than major depressive disorder (MDD) and (2) tolerability across all psychiatric disorders. Literature searches were performed up to January 2021, yielding 82 studies that met inclusion criteria, and 16 of these studies were included in the meta-analyses. Carriers of the 5-HTTLPR LL or LS genotypes were more likely to respond to antidepressant therapy, compared to the SS carriers in the total and European ancestry-only study populations. Long (L) allele carriers taking selective serotonin reuptake inhibitors (SSRIs) reported fewer ADRs relative to short/short (SS) carriers. European L carriers taking SSRIs had lower ADR rates than S carriers. These results suggest the 5-HTTLPR polymorphism may serve as a marker for antidepressant outcomes in psychiatric disorders and may be particularly relevant to SSRI treatment among individuals of European descent.

A Novel Biotinylated Homotryptamine Derivative for Quantum Dot Imaging of Serotonin Transporter in Live Cells

The serotonin transporter (SERT) is the primary target for selective serotonin reuptake inhibitor (SSRI) antidepressants that are thought to exert their therapeutic effects by increasing the synaptic concentration of serotonin. Consequently, probes that can be utilized to study cellular trafficking of SERT are valuable research tools. We have developed a novel ligand (IDT785) that is composed of a SERT antagonist (a tetrahydro pyridyl indole derivative) conjugated to a biotinylated poly ethylene glycol (PEG) via a phenethyl linker. This compound was determined to be biologically active and inhibited SERT-mediated reuptake of IDT307 with the half-maximal inhibitory concentration of 7.2 ± 0.3 μM. We demonstrated that IDT785 enabled quantum dot (QD) labeling of membrane SERT in transfected HEK-293 cultures that could be blocked using the high affinity serotonin reuptake inhibitor paroxetine. Molecular docking studies suggested that IDT785 might be binding to the extracellular vestibule binding site rather than the orthosteric substrate binding site, which could be attributable to the hydrophilicity of the PEG chain and the increased loss of degrees of freedom that would be required to penetrate into the orthosteric binding site. Using IDT785, we were able to study the membrane localization and membrane dynamics of YFP-SERT heterologously expressed in HEK-293 cells and demonstrated that SERT expression was enriched in the membrane edge and in thin cellular protrusions.

Pharmacogenetically Guided Escitalopram Treatment for Pediatric Anxiety Disorders: Protocol for a Double-Blind Randomized Trial

Current pharmacologic treatments for pediatric anxiety disorders (e.g., selective serotonin reuptake inhibitors (SSRIs)) frequently use "one size fits all" dosing strategies based on average responses in clinical trials. However, for some SSRIs, including escitalopram, variation in CYP2C19 activity produces substantial variation in medication exposure (i.e., blood medication concentrations). This raises an important question: would refining current SSRI dosing strategies based on CYP2C19 phenotypes increase response and reduce side effect burden? To answer this question, we designed a randomized, double-blind trial of adolescents 12-17 years of age with generalized, separation, and/or social anxiety disorders (N = 132). Patients are randomized (1:1) to standard escitalopram dosing or dosing based on validated CYP2C19 phenotypes for escitalopram metabolism. Using this approach, we will determine whether pharmacogenetically-guided treatment-compared to standard dosing-produces faster and greater reduction in anxiety symptoms (i.e., response) and improves tolerability (e.g., decreased risk of treatment-related activation and weight gain). Secondarily, we will examine pharmacodynamic variants associated with treatment outcomes, thus enhancing clinicians' ability to predict response and tolerability. Ultimately, developing a strategy to optimize dosing for individual patients could accelerate response while decreasing side effects-an immediate benefit to patients and their families. ClinicalTrials.gov Identifier: NCT04623099.

Autism and Emotion: A Narrative Review

Autism spectrum disorder (ASD) includes a variety of childhood-onset and lifelong neurodevelopmental condition with an enduring impact on multiple domains of functioning characterized by persistent deficits in social communication, restricted and repetitive behavior interest, and activities. They often find it hard to recognize and control emotions but their emotional expression can be improved by various intervention techniques that in turn can help them understand and respond more appropriately to other people. Problems in the area on emotional reciprocity among individual with ASD involve recognizing, understanding, expressing, and regulating emotions. Their ability in emotional reciprocity is often improved with a comprehensive treatment approach, especially by focused emotional enhancement intervention. In this review, we followed the standard IMRAD (Introduction, Methods, Results, and Discussion) structure to critically examine the condition of autism and its relation with genetic mechanism, and how theories of emotion and theory of mind associated with persons with ASD, some of the widely used assessment tools and future research direction in the emotional development of individuals diagnosed with ASD by using the narrative review method. Records collected through research databases such as Scopus, PubMed, Web of Science, Medline, EBSCO and published books with ISBN (International Standard Book Number), and published test manuals were evaluated in-depth and summarized based on the subtopic of the proposed title. A critical theoretical analysis of the genetic mechanism of emotions, theories of emotions, and theory of mind was explained in connection with ASD.

Toward Predicting Impact of Common Genetic Variants on Schizophrenia Clinical Responses With Antipsychotics: A Quantitative System Pharmacology Study

CNS disorders are lagging behind other indications in implementing genotype-dependent treatment algorithms for personalized medicine. This report uses a biophysically realistic computer model of an associative and dorsal motor cortico-striatal-thalamo-cortical loop and a working memory cortical model to investigate the pharmacodynamic effects of COMTVal158Met rs4680, 5-HTTLPR rs 25531 s/L and D2DRTaq1A1 genotypes on the clinical response of 7 antipsychotics. The effect of the genotypes on dopamine and serotonin dynamics and the level of target exposure for the drugs was calibrated from PET displacement studies. The simulations suggest strong gene-gene pharmacodynamic interactions unique to each antipsychotic. For PANSS Total, the D2DRTaq1 allele has the biggest impact, followed by the 5-HTTLPR rs25531. The A2A2 genotype improved efficacy for all drugs, with a more complex outcome for the 5-HTTLPR rs25531 genotype. Maximal range in PANSS Total for all 27 individual combinations is 3 (aripiprazole) to 5 points (clozapine). The 5-HTTLPR L/L with aripiprazole and risperidone and the D2DRTaq1A2A2 allele with haloperidol, clozapine and quetiapine reduce the motor side-effects with opposite effects for the s/s genotype. The COMT genotype has a limited effect on antipsychotic effect and EPS. For cognition, the COMT MM 5-HTTLPR L/L genotype combination has the best performance for all antipsychotics, except clozapine. Maximal difference is 25% of the total dynamic range in a 2-back working memory task. Aripiprazole is the medication that is best suited for the largest number of genotype combinations (10) followed by Clozapine and risperidone (6), haloperidol and olanzapine (3) and quetiapine and paliperidone for one genotype. In principle, the platform could identify the best antipsychotic treatment balancing efficacy and side-effects for a specific individual genotype. Once the predictions of this platform are validated in a clinical setting the platform has potential to support rational personalized treatment guidance in clinical practice.

Estradiol Influences Adenosinergic Signaling and NREM Sleep Need in Adult Female Rats

Gonadal steroids and gender are risk factors for sleep disruptions and insomnia in women. However, the relationship between ovarian steroids and sleep is poorly understood. In rodent models, estradiol (E2) suppresses sleep in females suggesting that E2 may reduce homeostatic sleep need. The current study investigates whether E2 decreases sleep need and the potential mechanisms that govern E2 suppression of sleep. Our previous findings suggest that the median preoptic nucleus (MnPO) is a key nexus for E2 action on sleep. Using behavioral, neurochemical and pharmacological approaches, we tested whether (1) E2 influenced the sleep homeostat and (2) E2 influenced adenosine signaling in the MnPO of adult female rats. In both unrestricted baseline sleep and recovery sleep from 6-hour sleep deprivation, E2 significantly reduced non-rapid eye movement sleep (NREM)-delta power, NREM-Slow Wave Activity (NREM-SWA, 0.5-4.0Hz), and NREM-delta energy suggesting that E2 decreases homeostatic sleep need. However, coordinate with E2-induced changes in physiological markers of homeostatic sleep was a marked increase in MnPO extracellular adenosine (a molecular marker of homeostatic sleep need) during unrestricted and recovery sleep in E2-treated but not oil control animals. While these results seemed contradictory, systemically administered E2 blocked the ability of CGS-21680 (adenosine A2A receptor agonist) microinjected into the MnPO to increase NREM sleep suggesting that E2 may block adenosine signaling. Together, these findings provide evidence that E2 may attenuate the local effects of the A2A receptors in the MnPO which in turn may underlie estrogenic suppression of sleep behavior as well as changes in homeostatic sleep need.

Associations of the MAOA uVNTR genotype and 5-HTTLPR/rs25531 haplotype with psychopathic traits

Previous studies have linked polymorphisms of the monoamine oxidase A (MAOA uVNTR) and serotonin transporter gene (5-HTTLPR) to individual differences in the expression of psychopathic traits, but findings remain inconsistent. One possible reason is that these studies have treated psychopathy as a unitary construct when there is accumulating evidence that there are variants or subtypes. We used a variable-centered and a person-centered approach by (a) examining putative genetic correlates of psychopathy across individuals and (b) comparing the frequencies of the MAOA uVNTR genotype and 5-HTTLPR/rs25531 haplotype between empirically derived subtypes of psychopathy, respectively. Notably, we included the often neglected rs25531 polymorphism, which is closely connected to the 5-HTTLPR. Based on data from male offenders and community volunteers, structural equation modeling indicated that the 5-HTTLPR/rs25531 haplotype was specifically associated with interpersonal deficits beyond the overarching psychopathy construct. Latent profile analysis revealed four clusters that were labeled non-psychopaths, sociopaths, callous-conning, and psychopaths. The low-activity variant of the 5-HTTLPR/rs25531 haplotype was significantly more frequent in the callous-conning compared to the non-psychopathic subtype. There were no effects for the MAOA uVNTR. The results illustrate that psychopathy should not be treated as a unitary construct but that there are variants with specific profiles of psychopathic traits, and that the 5-HTTLPR/rs25531 haplotype plays a role in the manifestation of interpersonal deficits from a variable-centered as well as from a person-centered view.

Maternal serotonin transporter genotype and offsprings' clinical and cognitive measures of ADHD and ASD

Serotonin (5-HT) is an important factor for prenatal neurodevelopment whereby its neurotrophic actions can be regulated through maternal-fetal interactions. We explored if maternal 5-HTTLPR genotype is associated with clinical and cognitive measures of attention-deficit/hyperactivity disorder (ADHD) and comorbid autism spectrum disorder (ASD) in typically-developing and ADHD-diagnosed offspring, beyond classical inheritance and environmental- and comorbidity-mediators/confounders. Family-based variance decomposition analyses were performed incorporating 6-31 year-old offsprings' as well as parental genotypes of 462 ADHD and control families from the NeuroIMAGE cohort. Dependent measures were offsprings' ADHD symptom- and ASD trait-scores and cognitive measures including executive functioning (including response inhibition and cognitive flexibility), sustained attention, reward processing, motor control, and emotion recognition. Offsprings' stereotyped behavior was predicted by an interaction between maternal 5-HTTLPR genotype and offsprings' sex. Furthermore, offspring of mothers with low-expressing genotypes demonstrated larger reward-related reductions in reaction time. While specifically adult male offspring of these mothers reported a faster reversal learning with less errors, specifically young female offspring of these mothers were more accurate in identifying happy faces. Adult offspring from the mothers with low-expressing 5-HTTLPR genotypes were also slower in identifying happy faces. However, this association seemed to be mediated by offsprings' high anxiety levels. In sum, we found some support for a role of the maternal 5-HT system in modulating fetal brain development and behavior. Offsprings' cognitive measures might be more sensitive to small alterations within the maternal 5-HT system than their ADHD and ASD clinical phenotypes. Further studies are needed to specify the association between maternal genotype and risk for neurodevelopmental disorders.

Candidate Genes and Pathways Associated with Gilles de la Tourette Syndrome-Where Are We?

Gilles de la Tourette syndrome (GTS) is a childhood-onset neurodevelopmental and -psychiatric tic-disorder of complex etiology which is often comorbid with obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD). Twin and family studies of GTS individuals have shown a high level of heritability suggesting, that genetic risk factors play an important role in disease etiology. However, the identification of major GTS susceptibility genes has been challenging, presumably due to the complex interplay between several genetic factors and environmental influences, low penetrance of each individual factor, genetic diversity in populations, and the presence of comorbid disorders. To understand the genetic components of GTS etiopathology, we conducted an extensive review of the literature, compiling the candidate susceptibility genes identified through various genetic approaches. Even though several strong candidate genes have hitherto been identified, none of these have turned out to be major susceptibility genes yet.