Psychiatric research in the Northern Finland Birth Cohort 1986 – a systematic review

Figures & data

Figure 1. Data collections of the psychiatric studies in the Northern Finland Birth Cohort 1986

Table 1. Statistically significant findings of risk factors for ADHD symptoms or diagnosis in the Northern Finland Birth Cohort 1986

Risk factors	Outcomes and risk estimates (95% confidence intervals)
Pregnancy-related risk factors
Maternal smoking before pregnancy	ADHD symptoms in childhood (ORs): 1.4 (1.0–2.0)^a [30]
Maternal smoking during pregnancy	In childhood (ORs): ADHD symptoms: 1.5 (1.1–2.1)^a [30], 1.6 (1.3–2.0)^b [31]; hyperactivity: 1.3 (1.1–1.6)^c [32]
High social adversity	ADHD symptoms in childhood (OR): 2.2 (1.4–3.3)^b [31]
Maternal thyroid-stimulating hormone concentration	Among girls in childhood (ORs): inattention 1.2 (1.0–1.4)^d, high total score 1.2 (1.0–1.5)^d, combined ADHD symptoms 1.4 (1.1–1.8)^d [33]
Prenatal exposure to synthetic glucocorticoids (sGC)	Inattention in childhood (β): 0.97 (0.16–1.80)^e, p = 0.02 [34]
Mother being overweight and gaining a large amount of weight during gestation	ADHD symptoms in childhood (OR): 2.1 (1.2–3.7)^f [35] (Nordic ADHD network result)
Placental weight	ADHD symptoms among boys in childhood (ORs): 1.1 (1.0–1.2)^g; in adolescence: 1.2 (1.0–1.4)^g [36]
Childhood-related risk factors
Divorced family	ADHD symptoms among boys in adolescence (ORs): 9.3 (1.5–3.4)^h [29]
Non-intact family	Hyperactive/impulsive symptoms (β): −0.17 (p < 0.01) [21]
Reconstructed family	In adolescence (ORs): ADHD symptoms among boys: 10.5 (2.1–3.5)^h; attention problems: among boys 1.6 (1.1–2.4)^h, girls 1.7 (1.3–2.3)^h [29]
Intellectual disability	Different hyperactive symptoms (ORs): being very restless 3.8 (2.3–6.3), being squirmy/fidgety child 4.2 (2.6–6.8), having poor concentration/short attention span 6.1 (3.7–10.1) [28]
Mixed handedness	In adolescence (ORs): inattention 3.0 (1.4–6.4)^i and ADHD symptoms 2.7 (1.2–6.0)^i [37]
Response inhibition	Inattentive symptoms (β): 0.23 (p < 0.001) and hyperactive/impulsive symptoms (β): 0.17 (p < 0.01) [21]
Childhood hyperactivity	ADHD diagnosis in adolescence (ORs) 3.3 (1.2–9.2)^j, for comorbid disruptive behavioural disorder and ADHD diagnoses 7.4 (2.6–21.1)^j [38]
Scholastic impairment in childhood	Comorbid disruptive behavioural disorder and ADHD diagnoses (OR): 3.1 (1.5–6.4)^j [38]
Major depression by age 13 years	Persisting ADHD diagnosis in adolescence (OR): 8.8 (1.1–68.5) [39]
Oppositional defiant disorder by age 13 years	Persisting ADHD diagnosis in adolescence (OR): 2.4 (1.0–5.6) [39]
Any hospital-treated injuries	Hyperactivity symptoms in childhood (HRs): 1.4 (1.0–1.9)^k; in adolescence: ADHD symptoms 1.5 (1.1–2.0)^k, diagnosis of ADHD 2.3 (1.2–4.5)^k [40]
Other risk factors
Allelic variants of the dopamine β-hydroxylase gene	ADHD symptoms in adolescence among males (ORs): 5.01 (1.8–14.5, marker rs2073837), 1.9 (1.0–3.5, rs1079727), 2.0 (1.1–3.7, rs 1,079,595), 2.1 (1.1–3.8, rs1124491), 1.9 (1.1–3.6, rs1800497) [41]

Abbreviations: ADHD = attention deficit hyperactivity disorder, OR = odds ratio, β = regression beta coefficient, HR = hazard ratio.

Adjusting factors:

^aGender, alcohol use during pregnancy, parental education and family structure.

^bSmoking during pregnancy, social adversity, birth weight and gestational age.

^cGender, maternal age, alcohol use during pregnancy, family structure and socioeconomic status.

^dSmoking during pregnancy, parity, maternal age and maternal education.

^eTotal prenatal sGC dose, interval between prenatal sGC exposure and birth, gender, smoking during pregnancy, parity, birth weight, placental weight, maternal age, parental education and family structure.

^fGender, smoking during pregnancy, gestational age, birth weight, maternal age, maternal education, family structure and cohort country.

^gMaternal pre-pregnancy body mass index, smoking during pregnancy, gestational weight gain and age, parity, birth weight, gestational age, parental education, family structure and socioeconomic status.

^hBirth order, parity, socioeconomic status.

ⁱGender, birth weight and gestational age.

^jGender, maternal tiredness during pregnancy, paternal smoking, family structure, being only child, hyperactivity at 8 years old, paternal admittance to inpatient psychiatric care.

^kGender, parity, family structure, socioeconomic status.

Table 2. Statistically significant findings of risk factors for emotional and behavioural problems in the Northern Finland Birth Cohort 1986

Risk factors	Outcomes and risk estimates (95% confidence intervals)
Pregnancy-related factors
Placental weight	Behavioural problems in childhood among boys (OR): 1.1 (1.0–1.3)^a [36]
Childhood-related risk factors
Single-parent family	In childhood (ORs): behavioural problems: among boys 1.8 (1.3–2.5)^b and girls 2.2 (1.3–3.7)^b; emotional problems: boys 2.0 (1.1–3.2)^b and girls 2.0 (1.1–3.5)^b [51]
Younger age in the classroom	In childhood (ORs): behavioural problems: 1.5 (1.3–1.8); emotional problems: 2.1 (1.7–2.7) [55]
Learning difficulties	In childhood (ORs): behavioural problems: among boys 3.1 (2.5–4.0)^c and girls 3.9 (2.6–5.8)^c; emotional problems: among boys 3.0 (2.0–4.6)^c and girls 5.3 (3.6–8.1)^c [56]
Intellectual disability	Mixed type of problems in childhood (OR): 5.6 (1.9–16.3) [28]
Other risk factors
Multi-site musculoskeletal pain at ages of 16 and 18 years	At the age of 18 years (RRs): distress among boys 3.5 (2.1–5.9)^d and girls 1.8 (1.2–2.7)^d; anxiety among boys 1.8 (1.4–2.3)^d and girls 1.5 (1.0–2.2)^d [8]
Physical inactivity	In adolescence (ORs): anxious/depressed symptoms among boys 2.9 (1.5–5.7)^e; withdrawn/depressed symptoms among boys 2.8 (1.8–4.2)^e and girls 2.3 (1.5–3.6)^e; somatic complaints among girls 1.4 (1.0–1.9)^e; rule-breaking behaviour among girls 1.8 (1.3–2.5)^e [55]

Abbreviations: OR = odds ratio, RR = risk ratio.

Adjusting factors:

^aMaternal pre-pregnancy body mass index and gestational weight gain, smoking during pregnancy, parity, gestational age, birth weight, maternal age, parental education, family structure, socioeconomic status.

^bBirth order, parity, maternal age at the time of the child’s birth, socioeconomic status and place of residence.

^cChild’s age, parental education, family structure, socioeconomic status and fine and gross motor skills.

^dBody mass index, level of physical activity, sitting and smoking status at 18 years.

^eBody mass index, family structure, income and parental education.

Figure 2. Summary of group differences between familial risk (FR) for psychosis and controls in functional and structural MRI studies in the Northern Finland Birth Cohort 1986. Blue represents decreased fMRI/MRI signal in FR (vs. controls) and red represents an increase in fMRI/MRI signal in FR (vs. controls)

Table 3. Statistically significant findings of risk factors for psychosis in the Northern Finland Birth Cohort 1986

Risk factors	Risk estimates (95% confidence intervals) for psychotic diagnoses
Adolescent physical inactivity	Any psychosis (OR): 3.3 (1.4–7.9)^a [75]
Increased CRP levels at adolescence	Schizophrenia (OR): 1.25 (1.1–1.5)^b [78]
Paternal neoplasms before age 18 years	Any psychosis (OR): 2.8 (1.4–5.6)^c [79]
Paternal factors influencing health status and contact with health services before 18y	Any psychosis (OR): 2.7 (1.4–5.3)^c [79]
Any adolescent cannabis use	Any psychosis (HR): 2.9 (1.7–4.7) [81]
Using cannabis more than 5 times	Any psychosis (HR): 3.0 (1.1–8.0)^d [81]
Adolescent tobacco (more than 10 cigarettes/day) use	Any psychosis (HR): 2.0 (1.1–3.5)^e [82]
Adolescent inhalant use more than 5 times	Any psychosis (HR): 3.1 (1.1–3.0)^f [83]
Two or more social problem items in PROD-screen in adolescence	Any psychosis (RR): 3.6 (2.1–6.1)^g [84]
Three or more social problem items in PROD-screen in adolescence	Any psychosis (RR): 6.2 (2.6–15.0)^g [84]

Abbreviations: CRP = C-reactive protein, OR = odds ratio, HR = Hazard ratio, RR = Risk ratio, PROD-screen = a screen for prodromal symptoms of psychosis.

Adjusting factors:

^aGender, family structure, parental socioeconomic status and parent’s physical activity.

^bGender, age, body mass index, smoking and alcohol use, and maternal education.

^cGender, perinatal complications, paternal age, parental socioeconomic status, parental psychiatric comorbidity and child’s cannabis use.

^dPROD-screen, other substance use, frequent alcohol use, daily tobacco smoking and parental psychosis.

^ePROD-screen, cannabis use, frequent alcohol use, other substance use, parental substance abuse and parental psychosis.

^fPROD-screen, cannabis use, comorbid mental disorder and parental substance use,

^gGender and parental psychosis.

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