Depressive and psychosomatic symptoms in twins with special reference to co-twin dependence.

We analyzed depressive and psychosomatic symptoms in relation to co-twin dependence in 419 twins at the age of 22 to 30 years. Depressive symptoms were assessed, as previously, with Children's Depression Inventory modified to be suitable for this age and reported as a total score and three subscales (low self-confidence, anhedonia and sadness) based on factor analysis as reported in a previous epidemiological study conducted in Finland. Items assessing nervous complaints and somatic symptoms were adapted from Finnish studies of juvenile health habits. Inter-twin dependence decreased with increasing age in both genders. Monozygotic twins, especially monozygotic females, reported most often to be dependent on their co-twin. When the symptom reporting was evaluated in relation to co-twin dependence, no relation was found between co-twin dependence and depressive symptom reporting. However, dependence-independence imbalance within twin pair was associated with elevated levels of depressive and psychosomatic symptoms, especially in twins who perceived themselves as dependent and the co-twin as independent. We conclude that there was no relation found between co-twin dependence and depressive symptom reporting in male and female twins except for the few imbalance cases, where most symptoms were reported by those dependent twins who felt their co-twin as independent.

Screening infants with social and emotional problems: a pilot study of the brief infant toddler social and emotional assessment (BITSEA) in Northern Finland.

OBJECTIVES: To compare 3 questionnaires used to evaluate early developmental problems, emotional disturbances and competence in 18-month-old infants. STUDY DESIGN: A follow-up study with parents of infants 8 to 36 months of age who responded to a developmental questionnaire. METHODS: Fifty infants (18 months of age) were evaluated through 3 questionnaires: (1) the Brief Infant and Toddler Social and Emotional Assessment (BITSEA), (2) the Child Behavior Checklist (CBCL) and (3) the MacArthur Communicative Development Inventories (MCDI). RESULTS: The BITSEA-questionnaire results (total problem scores) had a strong correlation with the most CBCL subscales and the MCDI (total scores) and gave more precise information concerning the infants' developmental problems. CONCLUSIONS: The BITSEA questionnaire identifies developmental problems in the early stages and screens infants' social-emotional competence.

A comparative assessment of the factor structures and psychometric properties of the GHQ-12 and the GHQ-20 based on data from a Finnish population-based sample.

The General Health Questionnaire (GHQ) is a self-report questionnaire designed to identify psychological distress. Psychometric properties of two versions of GHQ-12 and GHQ-20 were assessed in a large population-based sample of Finnish twins, ages 22 to 27 (n= 4580). Participants were randomized into two subgroups, namely Twin1 (n= 2294) and Twin2 (n= 2286). The GHQ-12 data were assessed using Confirmatory Factor Analysis (CFA). The factor structure of the GHQ-20 was first assessed with Exploratory Factor Analysis (EFA) in the Twin1 dataset, and the results obtained were then subjected to CFA in Twin1 and Twin2 datasets. The CFA of the GHQ-12 indicated that the best fit and the simplest solution were provided by the three-factor solution in both subpopulations. Analyses of the GHQ-20 suggested that the four-factor structure was superior to the three-factor model. This result is also theoretically justifiable. Compared to the 12-item version, GHQ-20 provides additional fourth factor of anhedonia, suggesting some discriminative power.

How long do the consequences of parental preference last: A study of twins from pregnancy to young adulthood.

We analyzed depressive and psychosomatic symptoms in relation to parental preference in 419 twins at the age of 22 to 30 years. Depressiveness was elicited with Children's Depression Inventory and reported as a total score and three subscales (low self-confidence, anhedonia and sadness) based on factor analysis as reported in a previous epidemiological study conducted in Finland. Items assessing nervous complaints and somatic symptoms were adapted from Finnish studies of juvenile health habits. Twins reported the preference in two directions: experienced parental preference towards either twin, and twin's own preference towards either parent. About half of the twins were from pairs where both twins experienced having been equally close to both parents, while about 30% were from 'equal and mother's' pair, where one twin evaluated having been preferred by the mother and the co-twin evaluated having been equally close to both parents. According to the twins' own preference, about one third of the twin pairs were 'both equal', one third 'both mother's' and one third 'equal and mother's'. Those male twins who were equally close to both parents (experienced parental preference) had least total depressiveness, while females in the intermediate situation had the highest self-confidence and least anhedonia and nervousness. According to twins' own preference, twins who felt equally close to both parents had the least depressiveness and anhedonia. The intermediate position seems to be the best alternative, as these twins had the least symptoms.

Co-twin dependence modifies heritability of abstinence and alcohol use: a population-based study of Finnish twins.

The role of co-twin dependence (twins' closeness or reliance on the co-twin) was examined as a moderator of genetic and environmental influences on alcohol use in adolescence and early adulthood in a large longitudinal population-based study of Finnish twins (FinnTwin16). The associations between co-twin dependence and alcohol use were studied first at an individual level in adolescence (n = 3362) and early adulthood (n = 2912). Then, maximum likelihood models were fit to the two waves of data from same-sex twin pairs to assess the differences and changes in genetic and environmental influences on alcohol use (abstinence, drinking frequency, intoxication frequency); N = 1342 pairs in adolescence, and N = 1078 pairs in early adulthood. Overall, no significant associations were found between co-twin dependence and individual alcohol use. However, co-twin dependence importantly modulated genetic effects on drinking habits, especially in adolescence, but also in early adulthood. Co-twin-dependent twins reported greater similarity in their alcohol-related behavior across all alcohol-use measures at both time points, and the role of genes and environments varied according to co-twin dependence. Shared environmental factors explained most of the variation in drinking among co-twin-dependent twins in adolescence and contributed to drinking to intoxication during early adulthood. In contrast, among co-twin-independent twin pairs, genetic variance contributed significantly to all alcohol-use measures at both time-points. An interdependent sibling relationship is an important modifier of drinking habits, and it appears to reduce the impact of inherited liabilities on alcohol-related behavior especially in adolescence.

Inter-twin relationships and mental health.

We evaluated dominance-submissiveness between co-twins and its relationship to mental health in a cohort study of 419 twins followed from pregnancy to 22-30 years of age. Dominance-submissiveness between co-twins was assessed from three separate perspectives: physical dominance, psychological dominance, and verbal dominance. Depressive, nervous, and psychosomatic symptoms were analyzed in different twin groups. In the physical domain, males were more commonly dominant than females at school age and in adulthood. Before and at school age, girls were more dominant than boys in the psychological and verbal domains, as well as in total dominance. These differences disappeared in adulthood, and 81% of adult twins felt themselves equal to their co-twin in total dominance. Submissiveness in the psychological domain seemed to be associated with increased depressiveness, nervous complaints and psychosomatic symptoms in males of male-female twin pairs. Verbally submissive males in same-sex twin pairs had more depression and psychosomatic symptoms. Among females of same-sex twin pairs, submissiveness in the psychological domain was most clearly associated with depressive symptoms, whereas psychological or verbal dominance-submissiveness among females from male-female twin pairs was not associated with symptoms. Psychologically dominant males and females of same-sex twin pairs expressed greater nervousness than did their co-twins. We conclude that being submissive, especially in the psychological domain, to a female twin partner seems to be stressful, whereas it is easier, especially for females, to be submissive to a male twin partner.