The risks for major psychiatric disorders in the siblings of probands with major depressive disorder.

Using a case-controlled study including siblings of major depression (MD) and control probands, born 1970-1990 and followed through 2018, we sought to clarify the degree to which the familial liability to MD is reflected in its clinical features, and the pattern of psychiatric disorders at elevated risk in the siblings of MD probands. The study population included full-siblings of 197,309 MD and matched 197,309 control probands. The proband-sibling tetrachoric correlation of for MD was +0.20. Both linear and quadratic effects of younger AAO and number of episodes significantly increased the risk of MD in siblings. Male sex, anxiety disorder, alcohol use disorder (AUD), inpatient treatment, psychotic symptoms, severity, and antidepressant prescription in MD probands increased the risk of MD in siblings. Cox proportional hazard models (hazard ratios, 95% CI) revealed a significantly increased risk of attention deficit hyperactivity disorder (1.82, 1.76-1.88), generalized anxiety disorder (1.79, 1.74-1.85), bipolar disorder (1.78, 1.70-1.85), MD (1.74, 1.72-1.76), obsessive-compulsive disorder (1.72, 1.65-1.80), phobic anxiety disorder (1.71, 1.65-1.76), and panic disorder (1.68, 1.64-1.72) in MD co-siblings. The HRs for AUD (1.64, 1.60-1.68), post-traumatic stress disorder (1.62, 1.59-1.66) were modestly lower, and the lowest was seen for schizophrenia (1.42, 1.30-1.54). The overall pattern of increased risk of these disorders was similar in reared-apart half-siblings and cousins of MD probands. Our findings suggest that MD is familial, and a range of important clinical factors predict its familial liability. The familial liability to MD, mostly due to genetic factors, is shared with a broad range of psychiatric disorders.

Extended Swedish Adoption Study of Adverse Stress Responses and Posttraumatic Stress Disorder.

Importance: Twin studies have found that posttraumatic stress disorder (PTSD) is influenced by both genetic and environmental factors within a generation. No study has used an adoption design, which can address questions about the degree and sources of cross-generational transmission of adverse stress responses (ASRs) and PTSD. Objectives: To examine whether ASRs or PTSD are transmitted from parents to offspring, and to clarify the relative importance of genes and rearing. Design, Setting, and Participants: This cohort study used nationwide Swedish registry data from parents and offspring (n = 2 194 171, born 1960-1992) of 6 types of families (intact; had not lived with biological father; had not lived with biological mother; lived with stepfather; lived with stepmother; and adoptive). Follow-up occurred on December 31, 2018, and data were analyzed from March 3, 2023, to January 16, 2024. Exposures: Three sources of parent-offspring resemblance: genes plus rearing, genes only, and rearing only. Main Outcomes and Measures: Diagnoses of ASRs or PTSD were obtained from national inpatient, outpatient, and primary care medical registries. Parent-child resemblance was assessed by tetrachoric correlation. Sensitivity analyses were conducted to control for possible shared traumatic events. Results: The study population included 2 194 171 individuals of 6 family types (1 146 703 [52.3%] male; median [range] age, 42 [20-63] years). The weighted tetrachoric correlations across family types were 0.15 (95% CI, 0.15-0.16) for genes plus rearing, 0.08 (95% CI, 0.06-0.11) for genes only, and 0.10 (95% CI, 0.07-0.12) for rearing only. Controlling for potential shared traumatic events, sensitivity analyses found that the correlation for rearing decreased, with the most conservative control (exclusion of parent-offspring dyads with onset of ASRs or PTSD within 1 year) suggesting equal correlations with genes and rearing. Conclusions and Relevance: Diagnosis of ASRs or PTSD demonstrated cross-generational transmission, including both genetic and rearing correlations. Sensitivity analyses suggested that shared traumatic events partially accounted for the observed rearing correlations.

Alcohol use disorder and risk of specific methods of suicide death in a national cohort.

INTRODUCTION: Alcohol use disorder (AUD) is among the strongest correlates of suicide death, but it is unclear whether AUD status is differentially associated with risk of suicide by particular methods. METHODS: The authors used competing risks models to evaluate the association between AUD status and risk of suicide by poisoning, suffocation, drowning, firearm, instruments, jumping, or other means in a large Swedish cohort born 1932-1995 (total N = 6,581,827; 48.8% female). Data were derived from Swedish national registers, including the Cause of Death Register and a range of medical registers. RESULTS: After adjusting for sociodemographic factors and familial liability to suicidal behavior, AUD was positively associated with risk of suicide for each method evaluated (cumulative incidence differences: 0.006-1.040 for females, 0.046-0.680 for males), except the association with firearm suicide in females. AUD was most strongly associated with risk of suicide by poisoning. Sex differences in the effects of AUD and family liability were observed for some, but not all, methods. Furthermore, high familial liability for suicidal behavior exacerbated AUD's impact on risk for suicide by poisoning (both sexes) and suffocation and jumping (males only), while the inverse interaction was observed for firearm suicide (males only). CONCLUSIONS: AUD increases risk of suicide by all methods examined and is particularly potent with respect to risk of suicide by poisoning. Differences in risk related to sex and familial liability to suicidal behavior underscore AUD's nuanced role in suicide risk. Future research should investigate targeted means restriction effectiveness among persons with AUD.

Pattern of Risks for Psychiatric and Substance Use Disorders in the Offspring of Parents With Alcohol Use Disorder.

OBJECTIVE: The authors sought to clarify the components of the familial liability to alcohol use disorder (AUD) by examining parent-offspring transmission in a large Swedish population sample. METHODS: To this end, 1,244,516 offspring in intact families with a mean age at follow-up of 37.7 years (SD=6.8) were examined. Hazard ratios for offspring of parents with AUD were calculated using Cox models for risk of five disorders assessed from Swedish medical and criminal registries: AUD, drug use disorders, attention deficit hyperactivity disorder, major depression, and anxiety disorders. RESULTS: The hazard ratio for the offspring was highest for AUD (hazard ratio=2.36), followed by drug use disorder (hazard ratio=2.04), attention deficit hyperactivity disorder (hazard ratio=1.82), major depression (hazard ratio=1.43), and anxiety disorder (hazard ratio=1.43). The risks for AUD were statistically indistinguishable between the children having mothers with AUD compared with those having fathers with AUD and between sons and daughters of a parent with AUD. All risks for offspring having two parents with AUD were higher than those having one parent with AUD, but the increase with two parents with AUD was greatest for AUD, followed by drug use disorder and attention deficit hyperactivity disorder. Age at AUD onset of the parents predicted risk among the offspring more strongly for AUD and drug use disorder, followed by attention deficit hyperactivity disorder, and then major depression and anxiety disorders. Number of recurrences of the parents with AUD predicted risks for all disorders equally. The risk pattern of disorders for the offspring of not-lived-with fathers with AUD was similar to that in the main analysis of intact families. No evidence was found for sex-specific transmission of AUD or a familial female protective effect. CONCLUSIONS: Familial and likely genetic liability to AUD has three components: a nonspecific risk of common internalizing and externalizing disorders, a moderately specific risk of externalizing disorders, and a highly specific risk of AUD.

The Nature of the Familial Risk for Psychosis in Bipolar Disorder.

BACKGROUND AND HYPOTHESIS: To clarify whether the familial liability to psychosis associated with bipolar disorder (BD) is nonspecific or has a greater effect on risk for psychosis in cases with prominent mood symptoms and/or a remitting course. STUDY DESIGN: We examined, in 984 809 offspring raised in intact families in Sweden, born 1980-1996 and followed-up through 2018, by multivariable Cox proportional hazards regression, risk in offspring of parents with BD for 7 psychotic disorders: Psychotic MD (PMD), psychotic BD (PBD), schizoaffective disorder (SAD), acute psychoses, psychosis NOS, delusional disorder (DD) and schizophrenia (SZ). Diagnoses were obtained from national registers. STUDY RESULTS: In the offspring of BD parents, the hazard ratios (HR) for these 7 disorders formed an inverted U-shaped curve, rising from 2.98 for PMD, to peak at 4.49 for PBD and 5.25 for SAD, and then declining to a HR of 3.48 for acute psychoses and 3.22 for psychosis NOS, to a low of 2.19 for DD and 2.33 for SZ. A similar pattern of risks was seen in offspring of mothers and fathers affected with BD and in offspring predicted from age at onset in their BD parent. CONCLUSIONS: The BD-associated risk for psychosis impacts most strongly on mood disorders, moderately on episodic psychotic syndromes, and least on chronic psychotic disorders. These results support prior clinical studies suggesting a qualitative difference in the familial substrate for psychosis occurring in BD and SZ.

Tumour Growth Models of Breast Cancer for Evaluating Early Detection-A Summary and a Simulation Study.

With the advent of nationwide mammography screening programmes, a number of natural history models of breast cancers have been developed and used to assess the effects of screening. The first half of this article provides an overview of a class of these models and describes how they can be used to study latent processes of tumour progression from observational data. The second half of the article describes a simulation study which applies a continuous growth model to illustrate how effects of extending the maximum age of the current Swedish screening programme from 74 to 80 can be evaluated. Compared to no screening, the current and extended programmes reduced breast cancer mortality by 18.5% and 21.7%, respectively. The proportion of screen-detected invasive cancers which were overdiagnosed was estimated to be 1.9% in the current programme and 2.9% in the extended programme. With the help of these breast cancer natural history models, we can better understand the latent processes, and better study the effects of breast cancer screening.

Obsessive-Compulsive Disorder and Its Cross-Generational Familial Association With Anxiety Disorders in a National Swedish Extended Adoption Study.

Importance: We know little about the transmission of obsessive-compulsive disorder (OCD) across generations. Objective: To evaluate the sources of parent-offspring transmission of OCD and familial cross-generational association with more typical anxiety disorders. Design, Setting, and Participants: This Swedish population register-based study analyzed data for offspring born in Sweden from 1960 to 1995 from the following 4 family types: intact, not-lived-with biological father, lived-with stepfather, and adoptive. Follow-up occurred on December 31, 2018, and data were analyzed from April 6, 2022, to September 26, 2022. Exposures: Three sources of parent-offspring resemblance: genes plus rearing, genes only, and rearing only. Main Outcomes and Measures: Diagnoses of OCD, all anxiety disorders, generalized anxiety disorder (GAD), social phobia, and panic disorder were obtained from national inpatient, outpatient, and primary care medical registers. Parent-child resemblance was assessed by tetrachoric correlation (r). Results: The offspring population consisted of 2 413 128 individuals; mean (SD) age at follow-up was 40.2 (10.7) years, 1 258 670 individuals (52.2%) were male, and 1 154 458 individuals (47.8%) were female. For each type of parent-child relationship, the best-estimate correlation for OCD for genes plus rearing was 0.19 (95% CI, 0.17 to 0.20); genes only, 0.18 (95% CI, 0.11 to 0.24); and rearing only, 0.04 (95% CI, -0.10 to 0.19). From bivariate adoption analyses, the cross-generational genetic correlations between OCD with anxiety disorder diagnostic categories were estimated as follows: for all anxiety disorders, 0.62 (95% CI, 0.46 to 0.77); GAD, 0.87 (95% CI, 0.53 to 1.00); social phobia, 0.70 (95% CI, 0.31 to 1.00); and panic disorder, 0.47 (95% CI, 0.20 to 0.73). Conclusions and Relevance: This Swedish population register-based study found that OCD was transmitted from parents to children largely through a genetic relationship, with rearing playing a minor role. Viewed cross-generationally, OCD and anxiety disorders were moderately genetically correlated, with the genetic correlations strongest between OCD and GAD, intermediate for OCD and social phobia, and weakest between OCD and panic disorder. These genetic correlations were modestly attenuated when diagnostic hierarchies were imposed before analysis.

Cross-generational transmission of genetic risk for alcohol and drug use disorders: the impact of substance availability on the specificity of genetic risk.

BACKGROUND: Among individuals with alcohol use disorder (AUD) and drug use disorder (DUD), is their genetic liability and its specificity moderated by substance availability? METHODS: Offspring (born 1960-1995) and their biological parents from three family types [not-lived-with (NLW) biological father, mother and adoptive] and their AUD and DUD diagnoses were ascertained from Swedish national registers. Parent-offspring resemblance was calculated by tetrachoric correlation. RESULTS: In Swedes born from 1960 to 1995, prevalence rates of AUD were stable while DUD rates increased substantially. Best-estimate tetrachoric correlations (±95% confidence intervals) between AUD in biological parents and AUD and DUD in their offspring were, respectively, +0.19 (0.18-0.20) and +0.18 (0.17-0.20). Parallel results from DUD in parents to AUD and DUD in children were +0.12 (0.10-0.13) and +0.27 (0.26-0.28). When divided into older and younger cohorts, the specificity of DUD transmission increased substantially over time, while the genetic correlation between AUD and DUD significantly decreased. CONCLUSIONS: Raised when alcohol was the preferred substance of abuse and illicit drugs highly stigmatized, AUD in parents reflected a general liability to substance use disorders, as they transmitted similar genetic risk for AUD and DUD to their children raised when both substances were widely available and relatively acceptable. DUD in parents, by contrast, reflected a more specific liability to DUD and, when transmitted to offspring, produced a considerably stronger risk for DUD than for AUD that increased over time. The magnitude and specificity of the genetic liability to psychoactive substances can be influenced by the availability of that substance.

An Extended Swedish Adoption Study of Anxiety Disorder and Its Cross-Generational Familial Relationship With Major Depression.

OBJECTIVE: To clarify, using an extended adoption design, the sources of parent-offspring transmission for anxiety disorder (AD) and its major subforms and their familial cross-generational relationship with major depression (MD). METHODS: Offspring (born 1960-1992) and their parents, from six family types (intact, not-lived-with biological father or mother, lived-with step-father or step-mother, and adoptive), were ascertained from Swedish national samples. Diagnoses were obtained from national medical registers. We assessed three sources of parent-child resemblance: genes plus rearing, genes only, and rearing only. To test comorbidity effects, single diagnoses were assigned in comorbid cases based on frequency and recency. RESULTS: For AD to AD parent-child transmission, best-estimate tetrachoric correlations for the three types of parent-offspring relationships genes plus rearing, genes only, and rearing only-equaled +0.16 (95% CI=0.16, 0.16), +0.12 (95% CI=0.10, 0.13), and +0.06 (95% CI=0.04, 0.07), respectively, with broadly similar results for MD to MD transmission. Cross-disorder cross-generation correlations were modestly lower, with genetic and rearing correlations for AD and MD estimated at +0.83 (95% CI=0.76, 0.90) and +0.83 (95% CI=0.69, 0.96), respectively. Analyses for panic disorder and generalized anxiety disorder (GAD) produced comparable findings, with the genetic correlation with MD modestly higher for generalized anxiety disorder than panic disorder. Applying a diagnostic hierarchy to comorbid cases resulted in a decline in cross-disorder cross-generation transmission with the estimated genetic correlation equaling +0.46 (95% CI=0.30, 0.62). CONCLUSIONS AND RELEVANCE: For AD and its major subforms, cross-generational transmission includes both genetic and rearing effects. In traditional analyses, AD and MD demonstrate highly correlated genetic and rearing effects. The genetic correlation weakened when applying a diagnostic hierarchy.

An Instrument for Measuring Social Participation to Examine Older Adults' Use of the Internet as a Social Platform: Development and Validation Study.

BACKGROUND: Older people's use of the internet is increasingly coming into focus with the demographic changes of a growing older population. Research reports several benefits of older people's internet use and highlights problems such as various forms of inequality in use within the group. There is a need for consistent measurements to follow the development and use of the internet in this group and to be able to compare groups both within and between countries, as well as follow the changes over time. OBJECTIVE: The aim of this study was to create an instrument to measure an older person's perception of the benefits of their online social participation, unconnected to specific applications and services. The instrument to measure internet social participation proposed in this paper builds on social participation factors and is a multidimensional construct incorporating both social relations and societal connectedness. METHODS: A short instrument for measuring social participation over the internet was created. An exploratory factor analysis (EFA) was conducted in a random selection of persons aged 65 years or older (n=193) on 10 initial items. Further validation was made by confirmatory factor analysis (CFA) in the remaining group (n=193). RESULTS: A 1-factor solution for the social internet score was decided upon after exploratory factor analysis (EFA; based on a random sample of half the data set). None of the questionnaire items were excluded based on the EFA, as they all had high loadings, the lowest being 0.61. The Cronbach α coefficient was .92. The 1-factor solution explained 55% of the variance. CFA was performed and included all 10 questionnaire items in a 1-factor solution. Indices of goodness of fit of the model showed room for improvement. Removal of 4 questions in a stepwise procedure resulted in a 6-item model (χ26=13.985; χ2/degrees of freedom=1.554; comparative fit index=0.992; root mean square error of approximation=0.054; standardized root mean square residual=0.025). CONCLUSIONS: The proposed instrument can be used to measure digital social participation and coherence with society. The factor analysis is based on a sufficient sample of the general population of older adults in Sweden, and overall the instrument performed as expected.

Older People's Use and Nonuse of the Internet in Sweden.

The use of the internet has considerably increased over recent years, and the importance of internet use has also grown as services have gone online. Sweden is largely an information society like other countries with high reported use amongst European countries. In line with digitalization development, society is also changing, and many activities and services today take place on the internet. This development could potentially lead to those older persons who do not use the internet or do not follow the development of services on the internet finding it difficult to take part in information and activities that no longer occur in the physical world. This has led to a digital divide between groups, where the older generations (60+), in particular, have been affected. In a large study of Sweden's adult population in 2019, 95 percent of the overall population was said to be internet users, and the corresponding number for users over 66 years of age was 84%. This study shows that the numbers reported about older peoples' internet use, most likely, are vastly overestimated and that real use is significantly lower, especially among the oldest age groups. We report that 62.4% of the study subjects are internet users and that this number most likely also is an overestimation. When looking at nonresponders to the questionnaire, we find that they display characteristics generally attributed to non-use, such as lower education, lower household economy, and lower cognitive functioning.

Continuous tumour growth models, lead time estimation and length bias in breast cancer screening studies.

Comparisons of survival times between screen-detected and symptomatically detected breast cancer cases are subject to lead time and length biases. Whilst the existence of these biases is well known, correction procedures for these are not always clear, as are not the interpretation of these biases. In this paper we derive, based on a recently developed continuous tumour growth model, conditional lead time distributions, using information on each individual's tumour size, screening history and percent mammographic density. We show how these distributions can be used to obtain an individual-based (conditional) procedure for correcting survival comparisons. In stratified analyses, our correction procedure works markedly better than a previously used unconditional lead time correction, based on multi-state Markov modelling. In a study of postmenopausal invasive breast cancer patients, we estimate that, in large (>12 mm) tumours, the multi-state Markov model correction over-corrects five-year survival by 2-3 percentage points. The traditional view of length bias is that tumours being present in a woman's breast for a long time, due to being slow-growing, have a greater chance of being screen-detected. This gives a survival advantage for screening cases which is not due to the earlier detection by screening. We use simulated data to share the new insight that, not only the tumour growth rate but also the symptomatic tumour size will affect the sampling procedure, and thus be a part of the length bias through any link between tumour size and survival. We explain how this has a bearing on how observable breast cancer-specific survival curves should be interpreted. We also propose an approach for correcting survival comparisons for the length bias.

Joint models of tumour size and lymph node spread for incident breast cancer cases in the presence of screening.

Continuous growth models show great potential for analysing cancer screening data. We recently described such a model for studying breast cancer tumour growth based on modelling tumour size at diagnosis, as a function of screening history, detection mode, and relevant patient characteristics. In this article, we describe how the approach can be extended to jointly model tumour size and number of lymph node metastases at diagnosis. We propose a new class of lymph node spread models which are biologically motivated and describe how they can be extended to incorporate random effects to allow for heterogeneity in underlying rates of spread. Our final model provides a dramatically better fit to empirical data on 1860 incident breast cancer cases than models in current use. We validate our lymph node spread model on an independent data set consisting of 3961 women diagnosed with invasive breast cancer.

E-Science technologies in a workflow for personalized medicine using cancer screening as a case study.

OBJECTIVE: We provide an e-Science perspective on the workflow from risk factor discovery and classification of disease to evaluation of personalized intervention programs. As case studies, we use personalized prostate and breast cancer screenings. MATERIALS AND METHODS: We describe an e-Science initiative in Sweden, e-Science for Cancer Prevention and Control (eCPC), which supports biomarker discovery and offers decision support for personalized intervention strategies. The generic eCPC contribution is a workflow with 4 nodes applied iteratively, and the concept of e-Science signifies systematic use of tools from the mathematical, statistical, data, and computer sciences. RESULTS: The eCPC workflow is illustrated through 2 case studies. For prostate cancer, an in-house personalized screening tool, the Stockholm-3 model (S3M), is presented as an alternative to prostate-specific antigen testing alone. S3M is evaluated in a trial setting and plans for rollout in the population are discussed. For breast cancer, new biomarkers based on breast density and molecular profiles are developed and the US multicenter Women Informed to Screen Depending on Measures (WISDOM) trial is referred to for evaluation. While current eCPC data management uses a traditional data warehouse model, we discuss eCPC-developed features of a coherent data integration platform. DISCUSSION AND CONCLUSION: E-Science tools are a key part of an evidence-based process for personalized medicine. This paper provides a structured workflow from data and models to evaluation of new personalized intervention strategies. The importance of multidisciplinary collaboration is emphasized. Importantly, the generic concepts of the suggested eCPC workflow are transferrable to other disease domains, although each disease will require tailored solutions.

A statistical model of breast cancer tumour growth with estimation of screening sensitivity as a function of mammographic density.

Understanding screening sensitivity and tumour progression is important for designing and evaluating screening programmes for breast cancer. Several approaches for estimating tumour growth rates have been described, some of which simultaneously estimate (mammography) screening sensitivity. None of the continuous tumour growth modelling approaches has incorporated mammographic density, although it is known to have a profound influence on mammographic screening sensitivity. We describe a new approach for estimating breast cancer tumour growth which builds on recently described continuous tumour growth models and estimates mammographic screening sensitivity as a function of tumour size and mammographic density.

Breast cancer tumour growth modelling for studying the association of body size with tumour growth rate and symptomatic detection using case-control data.

INTRODUCTION: A large body size is associated with larger breast cancer tumours at diagnosis. Standard regression models for tumour size at diagnosis are not sufficient for unravelling the mechanisms behind the association. METHODS: Using Swedish case-control data, we identified 1352 postmenopausal women with incident invasive breast cancer diagnosed between 1993 and 1995. We used a novel continuous tumour growth model, which models tumour sizes at diagnosis through three submodels: for tumour growth, time to symptomatic detection, and screening sensitivity. Tumour size at other time points is thought of as a latent variable. RESULTS: We quantified the relationship between body size with tumour growth and time to symptomatic detection. High body mass index and large breast size are, respectively, significantly associated with fast tumour growth rate and delayed time to symptomatic detection (combined P value = 5.0 × 10(-5) and individual P values = 0.089 and 0.022). We also quantified the role of mammographic density in screening sensitivity. CONCLUSIONS: The times at which tumours will be symptomatically detected may vary substantially between women with different breast sizes. The proposed tumour growth model represents a novel and useful approach for quantifying the effects of breast cancer risk factors on tumour growth and detection.