Does your iq change from childhood to adulthood
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Changes in IQ from Childhood to Adulthood
Stability of IQ Over Time
Research indicates that IQ tends to remain relatively stable from childhood to adulthood, although the degree of stability can vary. A longitudinal study assessing individuals from preschool to early adulthood found that general intelligence showed moderately high stability over time, with stability increasing as the intervals between assessments shortened and as individuals aged. This study also noted that children with initially higher IQ scores generally maintained their advantage into early adulthood, often pursuing higher educational tracks.
Impact of Birth Weight on IQ
Low birth weight (LBW) has been associated with lower IQ scores in childhood, adolescence, and early adulthood. A meta-analysis revealed that individuals with normal birth weight (NBW) scored significantly higher on IQ tests compared to those with LBW, although the impact of LBW on IQ diminished from childhood to young adulthood. This suggests that while LBW can have a lasting effect on cognitive development, its influence may decrease over time.
IQ in Autism Spectrum Disorders
For individuals with autism spectrum disorders (ASD) who had an average IQ in childhood, IQ levels generally remained stable into mid- to later adulthood. However, a subset of these individuals experienced significant declines in cognitive functioning, often associated with severe behavioral disturbances and language impairments. This highlights the variability in cognitive trajectories among individuals with ASD.
Early Growth and Adult IQ
Studies in low- and middle-income countries have shown that linear growth in the first two years of life is a strong predictor of IQ in adulthood. Growth in later childhood did not show a significant association with adult IQ, emphasizing the critical importance of early childhood development for long-term cognitive outcomes.
Childhood IQ and Psychiatric Disorders
Childhood IQ has been linked to the risk of developing psychiatric disorders in adulthood. Lower childhood IQ scores are associated with a higher risk of psychiatric illnesses, including schizophrenia and affective psychoses . Conversely, higher childhood IQ scores have been associated with an increased risk of bipolar disorder, suggesting that cognitive abilities in childhood can be predictive of various mental health outcomes later in life.
ADHD and IQ Trajectories
In individuals with ADHD, IQ deficits are evident from early childhood and persist into young adulthood. However, changes in ADHD symptoms over time do not appear to be directly reflected in changes in IQ. Those with persistent ADHD show the greatest cognitive deficits, followed by those whose symptoms remit or have a late onset.
Conclusion
Overall, while IQ tends to remain relatively stable from childhood to adulthood, various factors such as birth weight, early growth, and the presence of neurodevelopmental or psychiatric conditions can influence cognitive trajectories. Early childhood development plays a crucial role in determining long-term cognitive outcomes, and interventions during this period may have lasting benefits.
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