INTRODUCTION: Epidemiological studies of psychopathology in the first years of life are few, and the associations between mental health problems in infancy and toddler age and mental health disturbances later in life have not been systematically investigated. This study aimed to investigate whether markers of mental health problems can be identified in the first years of life and thus increase the scientific foundation for prevention early in childhood.

METHODS: The population studied was a birth cohort of children born in Copenhagen County in year 2000, the Copenhagen County Child Cohort 2000 (CCCC 2000), which has been followed prospectively from birth. Mental and physical health are described at baseline based on Danish national registers and standardised records from home visits made by public health nurses.

RESULTS: CCCC 2000 covers 6,090 children, of whom 5,624 (92%) have been described in health reports by public health nurses. In 13% of the cohort children, the general development was recorded as not normal, and in 12% language development was deviant. Problems with eating and sleeping were found frequently, in 30% and 20% of the children, respectively, and in 10% of the cases disturbances in the mother-child relationship were recorded.

CONCLUSION: The first results from CCCC 2000 show that risk factors and markers of mental disturbances can be identified in at least 10% of children in the general population. The validity of these results is currently being investigated in follow-up studies of CCCC 2000.