A three generations nation-wide population study of family load estimates in bipolar disorder with different age at onset

Biological rhythms disruption mediates the association between mother's diagnosis of bipolar disorder and offspring's emotional/behavioral problems

OBJECTIVE

The current study assesses whether the association between diagnosis of Bipolar Disorder (BD) in mothers and emotional and behavioral problems (EBP) in their offspring is mediated by a disruption in the offspring's biological rhythms.

METHODS

A probabilistic sample of 492 public school children (ages 7-8, 48 % female) were assessed for biological rhythms disruption and EBP using the Biological Rhythms Interview for Assessment in Neuropsychiatry for Kids and the Strengths and Difficulties Questionnaire, respectively. Mothers' mental health (BD = 64) was evaluated using a standardized clinical interview. A mediation analysis was conducted to assess the effect of the mother's diagnosis of BD on the EBP of their offspring in relation to the offspring's biological rhythms disruptions.

RESULTS

When compared to offspring of mothers without BD, offspring of mothers with BD showed greater difficulty in maintaining biological rhythms and higher prevalence of EBP. Using the presence of EBP as the outcome, 75 % of the effect of mother's BD diagnosis was mediated by offspring's biological rhythms disruption.

CONCLUSIONS

Biological rhythms disruption in children fully mediates the effect of the mother's diagnosis of BD on the child's EBP. These data encourage the development of further studies to find effective strategies to prevent and treat biological rhythms disruption in offspring of mothers with BD.

The U-shaped relationship between parental age and the risk of bipolar disorder in the offspring: A systematic review and meta-analysis

Parenthood age may affect the risk for the development of different psychiatric disorders in the offspring, including bipolar disorder (BD). The present systematic review and meta-analysis aimed to appraise the relationship between paternal age and risk for BD and to explore the eventual relationship between paternal age and age at onset of BD. We searched the MEDLINE, Scopus, Embase, PsycINFO online databases for original studies from inception, up to December 2021. Random-effects meta-analyses were conducted. Sixteen studies participated in the qualitative synthesis, of which k = 14 fetched quantitative data encompassing a total of 13,424,760 participants and 217,089 individuals with BD. Both fathers [adjusted for the age of other parent and socioeconomic status odd ratio - OR = 1.29(95%C.I. = 1.13-1.48)] and mothers aged ≤ 20 years [(OR = 1.23(95%C.I. = 1.14-1.33)] had consistently increased odds of BD diagnosis in their offspring compared to parents aged 25-29 years. Fathers aged ≥ 45 years [adjusted OR = 1.29 (95%C.I. = 1.15-1.46)] and mothers aged 35-39 years [OR = 1.10(95%C.I. = 1.01-1.19)] and 40 years or older [OR = 1.2(95% C.I. = 1.02-1.40)] likewise had inflated odds of BD diagnosis in their offspring compared to parents aged 25-29 years. Early and delayed parenthood are associated with an increased risk of BD in the offspring. Mechanisms underlying this association are largely unknown and may involve a complex interplay between psychosocial, genetic and biological factors, and with different impacts according to sex and age range. Evidence on the association between parental age and illness onset is still tentative but it points towards a possible specific effect of advanced paternal age on early BD-onset.

The impact of parental psychopathology and sociodemographic factors in selective mutism - a nationwide population-based study

BACKGROUND

Selective mutism (SM) is nowadays considered a relatively rare anxiety disorder characterized by children failing to speak in certain situations. Research on risk factors for SM are limited in comparison to other psychiatric disorders. The aim of this study was to examine several potential risk factors for SM in a large nationwide cohort, namely parental psychopathology, parental age, maternal SES, urbanicity, maternal marital status and parental immigration status.

METHODS

This nested case-control study comprised 860 cases with SM, identified from the Finnish Hospital Discharge Register and 3250 controls matched for sex and age from the Finnish Central Population Register. Conditional logistic regression was used to examine the association between the risk factors and SM.

RESULTS

If both parents had any psychiatric disorder, this almost tripled their odds of having a child with SM (OR 2.8, 95% CI 2.0-4.0). There were increased rates of all types of psychiatric disorders in the parents of the children with SM, with a wider range of diagnoses among the mothers than fathers. Fathers over 35 years (OR 1.4, 95% CI 1.1-1.8) were significantly more likely to have children with SM. Offspring of a single mother had a 2-fold (OR = 2.0, 95% CI 1.4-3.0) increased odds of SM than mothers who were married or in a relationship.

CONCLUSIONS

Several parental psychiatric disorders were associated with offspring SM. This points towards a shared aetiology of psychiatric disorders. Findings on paternal age and single motherhood help to improve our understanding of risk factors for SM.

Family aggregation and risk factors in substance use disorders over three generations in a nation-wide study

Objective

This nation-wide register-based study investigated how often substance use disorders (SUD) and co-morbid disorders occurred in affected families compared to control families.

Method

A total of N = 2504 child and adolescent psychiatric participants who were born between 1969 and 1986 and were registered in the Danish Psychiatric Central Research Register (DPCRR) had a mental disorder before the age of 18 and developed SUD at some point during their life-time. In addition, N = 7472 controls without any psychiatric diagnosis before age 18 and matched for age, sex, and residential region were included. Psychiatric diagnoses of the first-degree relatives were also obtained. A family load component was assessed.

Results

SUD occurred significantly more often in case families than in control families. SUD risk factors included SUD, depression, anxiety disorders, personality disorders, or conduct disorders in the family. Furthermore, male sex, more recent year of birth, and living in the capital city of Copenhagen were also significantly associated with having SUD. The family load explained 30% of the SUD manifestation in the case-probands. The findings in the total SUD group were mostly replicated in the two major subgroups of pure alcohol or multiple substance use disorders.

Discussion

These findings based on a very large and representative dataset provide additional evidence for the strong family aggregation and further risk factors in SUD. The pattern of risk factors is largely the same for the total group of SUD and the major subgroups of pure alcohol and multiple substance use disorders.

Family Aggregation and Risk Factors in Phobic Disorders over Three-Generations in a Nation-Wide Study

Objective

This nation-wide register-based study investigated how often phobic disorders (PHO) and co-morbid disorders occur in affected families compared to control families. Furthermore, the study addressed the impact of sex, year of birth, and degree of urbanization in terms of risk factors.

Method

A total of N = 746 child and adolescent psychiatric participants born between 1969 and 1986 and registered in the Danish Psychiatric Central Research Register (DPCRR) with a diagnosis of a mental disorder before the age of 18, and developed PHO at some point during their life-time until a maximum age of 40 years were included. In addition, N = 2229 controls without any diagnosis of mental disorders before age 18 and that were matched for age, sex, and residential region were included. Diagnoses of mental disorders were also obtained from the first- degree relatives as a part of the Danish Three Generation Study (3GS). A family load component was obtained by using various mixed regression models.

Results

PHO occurred significantly more often in case than in control families, in particular, in mothers and siblings. Substance use disorders (SUD), Depressive disorders (DEP), anxiety disorders (ANX) and personality disorders (PERS) in the family were significantly associated with specific phobia in the case-probands. After controlling for various mental disorders comorbid to PHO it was found that some of the family transmission could be caused by various other mental disorders in family members rather than the PHO itself. Female sex and more recent year of birth were further risk factors while region of residence was not related to the manifestation of PHO. Case-relatives did not develop PHO earlier than control relatives. After adjusting for various additional explanatory variables, the family load explained only 0.0013% of the variance in the manifestation of PHO in the case-probands

Discussion

These findings, based on a very large and representative dataset, provide evidence for the family aggregation and further risk factors in PHO. In contrast to anxiety disorders and other major mental disorders the family load of PHO in this nation-wide study was rather low.

Childhood-compared to adolescent-onset bipolar disorder has more statistically significant clinical correlates

BACKGROUND

The strengths and limitations of considering childhood-and adolescent-onset bipolar disorder (BD) separately versus together remain to be established. We assessed this issue.

METHODS

BD patients referred to the Stanford Bipolar Disorder Clinic during 2000-2011 were assessed with the Systematic Treatment Enhancement Program for BD Affective Disorders Evaluation. Patients with childhood- and adolescent-onset were compared to those with adult-onset for 7 unfavorable bipolar illness characteristics with replicated associations with early-onset patients.

RESULTS

Among 502 BD outpatients, those with childhood- (<13 years, N=110) and adolescent- (13-18 years, N=218) onset had significantly higher rates for 4/7 unfavorable illness characteristics, including lifetime comorbid anxiety disorder, at least ten lifetime mood episodes, lifetime alcohol use disorder, and prior suicide attempt, than those with adult-onset (>18 years, N=174). Childhood- but not adolescent-onset BD patients also had significantly higher rates of first-degree relative with mood disorder, lifetime substance use disorder, and rapid cycling in the prior year. Patients with pooled childhood/adolescent - compared to adult-onset had significantly higher rates for 5/7 of these unfavorable illness characteristics, while patients with childhood- compared to adolescent-onset had significantly higher rates for 4/7 of these unfavorable illness characteristics.

LIMITATIONS

Caucasian, insured, suburban, low substance abuse, American specialty clinic-referred sample limits generalizability. Onset age is based on retrospective recall.

CONCLUSIONS

Childhood- compared to adolescent-onset BD was more robustly related to unfavorable bipolar illness characteristics, so pooling these groups attenuated such relationships. Further study is warranted to determine the extent to which adolescent-onset BD represents an intermediate phenotype between childhood- and adult-onset BD.

A nation-wide study of the family aggregation and risk factors in anorexia nervosa over three generations

OBJECTIVE

This nation-wide register-based study investigated how often anorexia nervosa (AN) and co-morbid disorders occur in affected families compared with control families. Furthermore, the study addressed the impact of sex, year of birth, and degree of urbanization in terms of risk factors.

METHOD

A total of N = 2,370 child and adolescent psychiatric subjects born between 1951 and 1996 and registered in the Danish Psychiatric Central Research Register (DPCRR) had any mental disorder before the age of 18 and developed AN at some point during their life-time. In addition, N = 7,035 controls without any psychiatric diagnosis before age 18 and matched for age, sex, and residential region were included. Psychiatric diagnoses were also obtained on the first-degree relatives as a part of the Danish Three Generation Study (3GS). A family load component was obtained by using various mixed regression models.

RESULTS

AN occurred significantly more often in case than in control families. AN Risk factors included having a sibling with AN, affective disorders in family members, and co-morbid affective, anxiety, obsessive-compulsive, personality, or substance use disorders. Furthermore, female sex, and ascending year of birth were significantly associated with having AN. Urbanization was not related to the family load of AN and case-relatives did not develop AN earlier than control relatives.

DISCUSSION

These findings based on a very large and representative dataset provide evidence for the family aggregation and further risk factors in AN.

Bipolar disorder and parental psychopathology

PURPOSE

Few population-based studies have examined the association between parental psychopathology and bipolar disorder (BPD) in offspring. One limitation is lack of control for potential confounding by indicators of parental socio-economic status or maternal smoking during pregnancy. Furthermore, none of them included analyses restricted to parental diagnoses received prior to the birth of the offspring. Associations could not be affected by child-related factors affecting the parent in such analyses. This study explores associations between those parental psychiatric disorders diagnosed at any point of time as well as those diagnosed before offspring birth, and BPD in offspring.

METHODS

In this nested case-control study, we identified 1,861 cases, age up to 25 years, 3,643 matched controls, and their parents from Finnish national registers. The associations were examined using conditional logistic regression, calculating odds ratios (OR) and adjusting for region of birth, parental age and education and mother's smoking during pregnancy.

RESULTS

Anytime diagnosed parental disorders associating with BPD in offspring (95% confidence interval) were BPD [OR (maternal) 5.2 (2.52-10.62); OR (paternal) 8.1 (3.77-17.26)], schizophrenia and related psychoses [OR (maternal) 3.1 (1.69-5.84); OR (paternal) 4.5 (1.97-10.27)], other affective disorders [OR (maternal) 3.0 (2.08-4.21); OR (paternal) 3.0 (1.97-4.47)] and maternal anxiety disorders OR 2.6 (1.08-6.42). Statistically significant associations were also found for parental schizophrenia and related psychoses, and other affective disorders, diagnosed before offspring birth.

CONCLUSIONS

BPD is associated with many parental psychiatric disorders, particularly BPD and schizophrenia and related psychoses. The associations must be partially due to child-independent factors. Covariate adjustments had only a minor impact on the associations.

Commingling analysis of age-of-onset in bipolar I disorder and the morbid risk for major psychoses in first degree relatives of bipolar I probands

BACKGROUND

Age-of-onset (AO) is increasingly used in molecular genetics of bipolar I disorder (BP-I) as a phenotypic specifier with the goal of reducing genetic heterogeneity. However, questions regarding the cut-off age for defining early onset (EO), as well as the number of onset groups characterizing BP-I have emerged over the last decade with no definite conclusion. The aims of this paper are: 1) to see whether a mixture of three distributions better describes the AO of BP-I than a mixture of two distributions in different independent samples; 2) to compare the morbid risk (MR) for BP-I and for major affective disorders and schizophrenia in first degree relatives of BP-I probands by proband onset group derived from commingling analysis, since the MR to relatives is a trait with strong genetic background.

METHODS

We applied commingling (admixture) analysis to the AO of three BP-I samples from Romania (n=621), Germany (n=882), and Poland (n=354). Subsequently, the morbid risk (MR) for BP-I and for major psychoses (BP-I, BP-II, Mdd-UP, schizoaffective disorders, schizophrenia) was estimated in first degree relatives by proband AO-group derived from admixture analysis in the Romanian sample.

RESULTS

In the three independent samples and in the combined sample two- and three-AO-group distributions fitted the empirical data equally well. The upper EO limit varied between 21 and 25 years from sample to sample. The MR for both BP-I and for all major psychoses was similar in first degree relatives of EO probands (AO≤21) and in relatives of intermediate-onset probands (AO=22-34). Significant MR differences appeared only when comparing the EO group to the late-onset (LO) group (AO>34). Similar to Mdd-UP and schizophrenia, a significant MR decrease in proband first degree relatives was visible after proband AO of 34 years. Under the three-AO-group classification the MR for both BP-I and all major psychoses in first degree relatives did not differ by relative sex in any proband AO-group. Under the two-AO-group classification female relatives of LO probands (AO>24) had a significantly higher MR for all major psychoses than male relatives, while there was no sex difference for the relatives of EO probands.

LIMITATIONS

MR was not computed in the German and Polish samples because family data were not available and 34% of the relatives of the Romanian probands were not available for direct interview.

CONCLUSION

Similar to other clinical traits, the MR for major psychoses to relatives failed to support a three-AO-group classification in BP-I suggesting that this is not more useful for the molecular analysis than a two-AO-group classification.

Family load estimates and risk factors of anxiety disorders in a nationwide three generation study

The present study investigated how often anxiety disorders with different ages of onset occurred in affected families compared to control families. Furthermore, the study addressed the impact of sex, region of residence, year and month of birth, and parental age at birth. The sample included N=1373 child and adolescent psychiatric participants born between 1952 and 2000 and registered in the Danish Psychiatric Central Register (DPCR) who developed an anxiety disorder before the age of 18. N =4019 controls without any psychiatric diagnosis before age 18, were matched for age, sex, and residential region. Psychiatric diagnoses were also obtained for parents, siblings, and offspring. A family load component was obtained by using various mixed regression models. Anxiety disorders occurred significantly more often in case than in control families. Having a mother, father, or a sibling with the disorder was proven to be a risk factor. Female sex, year of birth, and region of residence were also associated with having an anxiety disorder. Furthermore, case relatives did not develop an anxiety disorder earlier than control relatives. These findings, based on a very large and representative dataset, provide further and solid evidence for the family aggregation of anxiety disorders.

Family aggregation and risk factors of obsessive-compulsive disorders in a nationwide three-generation study

BACKGROUND

This nationwide register-based study investigates how often obsessive-compulsive disorders (OCD) with different age at diagnosis occur in affected families compared to control families. Furthermore, the study addresses the impact of certain risk factors, that is, sex, degree of urbanization, year of birth, and maternal and paternal age at birth.

METHODS

A total of N = 2,057 child and adolescent psychiatric subjects born between 1952 and 2000 and registered in the Danish Psychiatric Central Research Register developed OCD before the age of 18. In addition, N = 6,055 controls without any psychiatric diagnosis before age 18 and matched for age, sex, and residential region were included. Psychiatric diagnoses were also obtained for the first-degree relatives as a part of the Danish Three-Generation Study. A family load component was obtained by using various mixed regression models.

RESULTS

OCD occurred significantly more often in case than in control families. Having a mother, father, sibling, or an offspring with the disorder was proven to be a risk factor. Maternal age above 35 years, male sex by tendency, and ascending year of birth were associated with having OCD. Furthermore, case relatives did not develop OCD earlier than control relatives. The risk of OCD in the case probands was significantly increased when first-degree family members had either OCD, or tic disorders, or affective disorders, or anxiety disorders.

CONCLUSIONS

These findings based on a very large and representative dataset provide further and very solid evidence for the high family aggregation of OCD.