Approximately 10-15% of young people suffer unexplained somatic symptoms that have a great impact on their lives. Researcher Karin Janssens from the University Medical Center Groningen has explored the possible causes of these symptoms. Janssens’ research shows that unexplained somatic symptoms in adolescents are related to biological processes (physical reaction to stress, puberty), psychological risk factors (anxiety, depression and stress during a stress test) and social risk factors (over-protective parents, missing school). Janssens used data collected from 2,230 adolescents as part of the long-term TRAILS research. She will be awarded a PhD for her research findings on 5 October 2011 at the University of Groningen.
Unexplained somatic symptoms are often associated with stress, so Janssens also looked into the effect of the stress hormone cortisol. Adolescents with low levels of cortisol on waking were more susceptible to fatigue, dizziness and sore muscles. Those with low levels of cortisol at times of stress suffered headaches and abdominal symptoms. The activity of the autonomic nervous system also varied according to the symptoms. More cases of fatigue, dizziness and sore muscles were reported by adolescents with a variable heart rate at rest, while more adolescents with a high heart rate at rest reported headaches and abdominal pain. Furthermore, fatigue, dizziness and sore muscles worsened during puberty, while headaches and abdominal pain did not. It would therefore be advisable to distinguish between different types of symptoms when researching the biological processes affecting unexplained somatic symptoms.
In her research into the psychological factors, Janssens tried to discover whether the adolescents had suffered anxiety or depression before the somatic symptoms started, or if they occurred as a result. She showed that anxious or depressed adolescents were more likely to develop unexplained somatic symptoms, and that in turn, the symptoms could make them more anxious and depressed. The role of the parents was highlighted in a study of over-protective parents. Young people claiming to have over-protective parents in the first measurement, reported more symptoms during subsequent measurements.
Pupils who frequently missed school reported more somatic symptoms during subsequent measurements than pupils with a good attendance rate. This effect was not noted in adolescents who were bullied. In general, missing school probably has an adverse effect on the course of the ailments, as adolescents have more time to focus on their symptoms when at home. Adolescents who are bullied probably experience less stress at home than at school, so missing school probably has both a favourable and an adverse effect on their symptoms.
TRAILS is a study of the physical and mental development of children into adulthood, which started in 2000. As part of the study, 2,230 children in the three provinces in the north of the Netherlands are being monitored from 10 until 25 years of age. Janssens used data from the first three measurements, when the children were an average of 11, 13.5 and 16 years old.
Karin Janssens (Nijmegen, 1984) studied Medicine at the University of Groningen. She carried out her research as part of the UMCG long-term TRAILS study. Her thesis is entitled: ‘The etiology of functional somatic symptoms in adolescents. A new perspective on lumping and splitting.’
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