Attention deficit hyperactivity disorder (ADHD) is a controversial developmental neuropsychiatric disorder in which there are significant problems with executive functions (e.g. attention control and lack of inhibition) that cause attention deficits, hyperactivity or impulsiveness. Its prevalence in children is between 1% and 8% depending on which diagnostic criteria are used.
Signs and symptoms of ADHD include but are not limited to difficulty focusing, inability to follow instructions, frequent fidgeting and excessive chatting.
ADHD was first identified to the 1920s and stimulants such as amphetamine were first used in the 1940s. One of the most dramatic and paradoxical clinical changes one can see in clinical psychiatry is the effect of speed (amphetamine, Ritalin, Adderall) on a child with ADHD. On the first visit the child is running around the office, into everything, cannot sit still etc., but after taking speed the child sits calm and still.
It appears as if the prevalence of ADHD is increasing over time. Some studies show 6% of our children are taking stimulants. Is this because schools are so boring that the children can’t pay attention, is it due to changes in diagnosis, or is the prevalence of ADHD really increasing?
For the first time, a group in Spain has shown that low vitamin D levels during pregnancy are associated with an increased risk of subsequent ADHD in the child.
Morales E, Julvez J, Torrent M, Ballester F, Rodríguez-Bernal CL, Andiarena A, Vegas O, Castilla AM, Rodriguez-Dehli C, Tardón A, Sunyer J. Vitamin D in Pregnancy and Attention Deficit Hyperactivity Disorder-like Symptoms in Childhood. Epidemiology. 2015 Apr 10. [Epub ahead of print].
Dr. Eva Morales, working under Professor Jordi Sunyer, studied 1,650 four-year-old children whose mothers had a vitamin D level measured at some time during pregnancy. Overall, 19% of the women had deficient (<20 ng/ml) and 33% had insufficient (20–29.99 ng/ml) levels of 25(OH)D while 48% had levels above 30 ng/ml. These are higher levels than seen in pregnant women in the USA, perhaps due to 25(OH)D detection method (the authors used high performance liquid chromatography). The prevalence of ADHD in the children ranged from 2% to 7% depending on how one measured it (DSM-IV vs. ICD-10).
As shown in the figure below, the risk of ADHD symptoms decreased as maternal 25(OH)D increased up to around 40 – 50 ng/ml when no further effect was seen.
You can’t see it clearly but maternal vitamin D status appeared to explain much of the ADHD symptoms in the children. That is, when maternal 25(OH)D levels were above 40 ng/ml, the average child had no ADHD symptoms.
The Vitamin D Council recommends that pregnant women sunbathe when possible, otherwise take at least 5,000 IU/day of vitamin D. It may be that one of the benefits of doing so is a reduced risk of your child getting ADHD.