In their National Survey of Health & Development psychiatrists looked at over 5,000 people born in 1946 and took diagnostic measures at 5 points in their lives up to age 53.
They analysed the data and identified 6 distinct categories which they called life course trajectories.
- 45% were symptom-free throughout their lives.
- 34% had persistent minor symptoms.
- 11% had few symptoms in adolescence with minor symptoms in adulthood
- 6% had symptoms in childhood but not in adulthood.
- 3% had few symptoms in childhood but suffered severe symptoms in adulthood
- Almost 2% had persistently severe symptoms all their lives.
So what were the key factors that influenced these outcomes?
Birth weight and the age at which they first stood and walked were good predictors. The heavier the baby and the earlier they walked the less likely they were to show psychiatric symptoms later in life.
This is because low birth weight and delayed developmental milestones were indicative of poor conditions for the baby in the womb.
In their paper in Biological Psychiatry the researchers think their findings add to the general consensus that adverse conditions for the foetus can have significant implications for the baby’s neurodevelopment and could permanently alter the stress response resulting in a lifetime of poor mental health.
However the authors are at pains to point out that this data doesn’t tell the whole story and consideration has to be given to other facts like stressful life events, poor physical health, and genetics. The nature-nurture discussion continues!
Other research suggests that mothers who are stressed during pregnancy have a greater chance of producing children with Attention Deficit Hyperactive Disorder (ADHD). Neurologists at the Institute of Psychiatry in London studied thousands of children from before birth to primary school and found a strong link between antenatal stress, mixed-handedness – the use of different hands for different tasks ie not ambidexterity, and childhood behavioural problems of which ADHD was the most common.
Their findings suggest that stress hormones in the womb disrupt the normal passage of neurons between the two hemispheres of the brain resulting in the inability for one hand to become dominant and a range of behavioural problems. Mixed handedness might in fact be an early indicator of ADHD as other research in Nordic countries showed that mixed-handed children, perhaps 5% of the population, are twice as likely to have ADHD symptoms than right-handed children. Previous studies have also shown links between ante-natal stress and low birthweight and low IQ.
Research at Imperial College found that problems with partners was a bigger cause of stress than worries about health , work or finances.
ADHD it is said to affect about 5% of the population and makes children (and some adults) appear reckless and impulsive with trouble concentrating. It can be treated with talking therapies such as CBT but Ritalin and similar drugs are commonly prescribed. But other experts dispute its existence as there is no diagnostic test and they see it as an excuse for poor behaviour. There is also concern about prescribing Ritalin and similar drugs as the number of prescriptions has increased dramatically from 3,500 in 1993 to over 600,000 in 2009.
Sources: The Psychologist & The Times