Social adjustment could be associated with the serotonin transporter gene in remitted patients with mood disorders and healthy subjects

The effect of serotonin transporter gene promoter polymorphism on adolescent and adult ADHD symptoms and educational attainment: A longitudinal study

Introduction:

The purpose of this longitudinal study was to investigate the relationship between the 5-HTTLPR genotype, symptoms of ADHD in adolescence and adulthood, and educational attainment in a population representative sample. Neuroticism, depressive symptoms and general mental abilities were controlled for as possible confounding factors.

Methods:

ADHD symptoms were reported at age 15 and 18 by teachers using the Hyperactivity Scale of af Klinteberg and SNAP-IV, and self-reported at age 25 using the ASRS. Data about education were reported at age 25.

Results:

At age 15, subjects with the l/l genotype had more concentration difficulties compared to s-allele carriers, and they also had more inattention symptoms according to SNAP-IV at age 18. These results were not altered by taking neuroticism or depressive symptoms into account. No 5-HTTLPR genotype effect on self-reported ADHD symptoms at age 25 was found. Inattention symptoms in adolescence were associated with lower education in young adulthood. The proportion of subjects with higher education at age 25 was significantly larger among s/s genotype compared to the l/l or s/l genotype.

Conclusions:

The l/l genotype of the 5-HTTLPR is associated with inattentive symptoms during adolescence in the general population, and increases the likelihood of inferior educational level in young adulthood.

Associations of the serotonin transporter promoter polymorphism (5-HTTLPR) with bipolar disorder and treatment response: A systematic review and meta-analysis

BACKGROUND

Associations of the serotonin transporter promoter polymorphism (5-HTTLPR) with bipolar disorder (BPD) and treatment response in bipolar patients were not conclusive. This study not only assessed the association between the 5-HTTLPR and BPD with accumulating relevant studies, but also in the first time evaluated the effect of the 5-HTTLPR on both anti-depressive and anti-manic treatment responses in bipolar patients.

METHODS

PubMed, Embase, PsycINFO, Cochrane Library and Cochrane Control Trials databases were systematically searched before February 2017. This meta-analysis followed the PRISMA guidelines.

RESULTS

A total of 32 population-based studies (5567 cases and 6993 controls) and 9 family-based studies (837 trios) were finally screened out and statistically joined into a single meta-analysis that revealed an association between S allele and an increased risk of BPD (OR = 1.06, p = .038). Pooled analysis of the 32 population-based studies indicated an association of S-carrier genotypes with an increased risk of BPD (OR = 1.10, p = .029). Meanwhile, the association remained significant in Caucasians (OR = 1.15, p = .004), which could provide an enough power (88%) to detect a significant association. Regarding the treatment response studies, 6 studies reporting the relationship of the 5-HTTLPR in anti-depressive remission rate (1034 patients) and 7 studies reporting in response rate (1098 patients) were included for pooled analyses. We observed a significant association of S-carrier genotypes with a reduced anti-depressive remission rate (OR = 0.64, p = .006) but not with anti-depressive response rate. The association between the 5-HTTLPR with anti-manic response rate was not observed in the included 6 studies (676 patients).

CONCLUSIONS

The present study supported the presence of a marginal but detectable effect of the 5-HTTLPR on susceptibility to BPD. Moreover, the detected association in Caucasian was statistically reliable. Besides, the 5-HTTLPR was identified as a useful predictor for anti-depressive remission but not for anti-depressive or anti-manic response.

Variation in the HTR1A and HTR2A genes and social adjustment in depressed patients

BACKGROUND

Social adjustment is impaired in depressed patients. The difficulty to adjust to social circumstances has been hypothesized to be one of the causes of depression, as well as a consequence of the disorder. Genetic variation in the serotonin transporter gene has been previously associated with social adjustment levels in patients with mood disorders.

METHODS

We investigated whether variations on the HTR1A (rs6295) and HTR2A (rs7997012) genes were associated with levels of social adjustment using the Social Adjustment Scale in two samples of depressed patients (total n=156).

RESULTS

Patients carrying the GG genotype of the HTR2A-rs7997012 showed better social adjustment in areas of work and family unit bonding.

LIMITATIONS

These findings did not survive correction for multiple testing and should be interpreted with caution.

CONCLUSION

Our finding is in line with previous observations that have associated the G allele of the HTR2A-rs7997012 with higher rate of antidepressant response. The HTR2A-rs7997012 is worthy of further investigation in studies examining factors that are related to depression course and outcome.

Droplets of black bile? Development of vulnerability and resilience to depression in young age

Major depressive disorder is predicted by enduring anxiety-related personality traits, in particular by neuroticism, which have genetic foundations. Neuroticism in turn is strongly related with the genetic risk for depression. Search for gene variants associated with neuroticism and depression has led to some good candidates, but the consistency of findings is very far from ideal. Adverse life events are causal to development of mood disorders, and often the vulnerability genes can be detected only when environmental impact has been objectively assessed. Yet the continuity of depression diagnosis from early childhood to adulthood is limited, while childhood depression increases odds of other affect-related disorders such as substance abuse and personality disorders. Whether specific genes have an impact seems to depend on the period of life both because of biological maturation and differences in major environmental factors, but also active engagement--or the failure to do so--of the vulnerable subjects with their environment. It is proposed that subjects with genetically determined neurotic tendencies are likely to attempt to select coping strategies that reduce events perceived as harmful and can by this means develop resilience towards affective disorders.

Serotonin transporter gene promoter region polymorphism and selective processing of emotional images

Several studies have now documented that the serotonin transporter promoter region (5-HTTLPR) polymorphism predicts neural response to affective images in brain regions involved in the experience of emotion. However, the behavioral consequences of this genetic effect are less well known. The current study used eye-tracking methodology to examine how individuals genotyped for the 5-HTTLPR allocated their attention when simultaneously presented an array of positive and negative emotional scenes. Short 5-HTTLPR allele homozygotes displayed a bias to focus on positive images, particularly in the first half of the 30s trial. In contrast, long 5-HTTLPR allele homozygotes viewed the stimuli in a more evenhanded fashion. Thus, short 5-HTTLPR allele homozygotes may be attempting to regulate greater reactivity to negative stimuli by purposefully turning their attention towards positive stimuli. Although this sensitivity may have benefits under benign conditions, it may also increase vulnerability to affective disorders when cognitive resources needed to turn attention away from negative stimuli are compromised.

How do genes exert their role? Period 3 gene variants and possible influences on mood disorder phenotypes

The action of multiple liability genes is responsible for complex phenotypes at the same time, a single gene, could control several phenotypic features. This is the case of human period 3 gene (hper3), mainly involved in the setting of the biologic clock. Some variants of this gene, besides being associated with the Delayed Sleep Phase Syndrome, showed a key role in determining evening preference rather than morning one. According to this rationale, we hypothesized that this gene could influence circadian mood fluctuations, in mood disorders. Our study demonstrated that rare genetic variants of hper3 are significantly associated to a number of mood disorders features, such as age of onset, response to SSRIs treatment, circadian mood oscillations and characteristics of temperament. These preliminary results could shed further light on the involvement of circadian genes in various aspects of physiological and psychopathological mechanisms of the brain.

Serotonin transporter gene influences the time course of improvement of "core" depressive and somatic anxiety symptoms during treatment with SSRIs for recurrent mood disorders

The short variant of the serotonin transporter gene (SERTPR) has been consistently associated with a poorer response to treatment with various selective serotonin reuptake inhibitors (SSRIs). Antidepressant response is not a unitary phenomenon, however, and we here hypothesized that the SERTPR effect could be specific to some types of symptomatology. The sample comprised 281 inpatients affected by mood disorders and treated for major depression with SSRIs. The total depressive scores for all patients were analyzed in previous reports, but symptomatologic clusters were not examined previously. The 21-item Hamilton Rating Scale for Depression (HAM-D) was administered to evaluate depressive symptoms at baseline and weekly over 6 weeks of treatment. All patients were genotyped for the SERTPR polymorphism. Compared with patients with the SERTPR l/l and l/s polymorphisms, s/s patients showed a selective and slower improvement of depressive "core" and somatic anxiety symptoms, but they did not differ from other patients regarding other symptomatologic clusters such as insomnia and motor retardation. These findings support the view that response to SSRIs is not a unitary phenomenon and that improvement of symptomatologic clusters as, at least in part, genetically driven. SERTPR may be hypothesized as concurrently participating to the activity of anatomic brain regions differentially involved in depression and somatic symptoms of anxiety; however, further studies are required to examine these complex interactions.

Temperament and character in mood disorders: influence of DRD4, SERTPR, TPH and MAO-A polymorphisms

Gene variants exert a complex range of effects on human normal and abnormal behavior. We previously reported the effect of gene variants in serotoninergic and dopaminergic pathways, in a range of clinical features in mood disorders, such as symptomathology, periodicity, social adjustment and treatment response. In this paper we hypothesized that the same gene variants could influence temperamental traits in mood disorders patients. We focused on genes of the serotoninergic and dopaminergic systems (dopamine receptor D4 gene, DRD4; serotonin transporter gene, promoter region SERTPR; tryptophan hydroxylase gene, TPH; monoamine oxidase A gene, MAO-A). Two hundred and seven euthymic subjects, affected by major depressive disorder (n=73) and bipolar disorder (n=134) were assessed by the Cloninger's Temperament and Character Inventory (TCI) and typed using PCR-based analyses. Possible stratification factors such as demographic, clinical and other temperamental factors were also taken into account. We observed that homozygosity for the short SERTPR allele was associated with low novelty-seeking scores (p=0.006) and genotypes containing the DRD4 long allele were marginally associated with low harm avoidance (p=0.05). Finally, the long MAO-A allele was associated with decreased persistence scores among females (p=0.006). Our observation of a pattern of influence on temperamental dimension exerted by serotonergic and dopaminergic genes suggests that the contribution of these polymorphisms to the clinical presentation of mood disorders could be mediated by an influence on personality differences.