Early childhood and adolescent risk factors for psychotic depression in a general population birth cohort sample

• Published in: Social Psychiatry and Psychiatric Epidemiology
• Main Authors: Nietola, Miika, Huovinen, Hanna, Heiskala, Anni, Nordström, Tanja, Miettunen, Jouko, Korkeila, Jyrki, Jääskeläinen, Erika
• Format: Text
• Language: English
• Published: Springer Berlin Heidelberg 2020
• Subjects: Original Paper; Northern Finland
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7471190/; http://www.ncbi.nlm.nih.gov/pubmed/32055894; https://doi.org/10.1007/s00127-020-01835-7

BACKGROUND AND PURPOSE: In the group of severe mental disorders, psychotic depression (PD) is essentially under-researched. Knowledge about the risk factors is scarce and this applies especially to early risk factors. Our aim was to study early childhood and adolescent risk factors of PD in a representative birth cohort sample with a follow-up of up to 50 years. METHODS: The study was carried out using the Northern Finland Birth Cohort 1966 (NFBC 1966). We used non-psychotic depression (NPD) (n = 746), schizophrenia (SZ) (n = 195), psychotic bipolar disorder (PBD) (n = 27), other psychoses (PNOS) (n = 136) and healthy controls (HC) (n = 8200) as comparison groups for PD (n = 58). We analysed several potential early risk factors from time of birth until the age of 16 years. RESULTS: The main finding was that parents’ psychiatric illness [HR 3.59 (1.84–7.04)] was a risk factor and a high sports grade in school was a protective factor [HR 0.29 (0.11–0.73)] for PD also after adjusting for covariates in the multivariate Cox regression model. Parental psychotic illness was an especially strong risk factor for PD. The PD subjects had a parent with psychiatric illness significantly more often (p < 0.05) than NPD subjects. Differences between PD and other disorder groups were otherwise small. CONCLUSIONS: A low sports grade in school may be a risk factor for PD. Psychiatric illnesses, especially psychoses, are common in the parents of PD subjects. A surprisingly low number of statistically significant risk factors may have resulted from the size of the PD sample and the underlying heterogeneity of the etiology of PD. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00127-020-01835-7) contains supplementary material, which is available to authorized users.