Table 1.
Selected population-based studies of childhood infection and schizophrenia and other psychotic disorder.
| Study | Design, sample and type of infection | Outcome and diagnostic criteria | Age of infection, max (years) | Data source | Age at follow up (years) | Cumulative incidence of schizophrenia (%) | Adjustment for confounding | NOS scoraStudy strengths and limitations |
|---|---|---|---|---|---|---|---|---|
| Weiser et al. (2010) | Case control: | Schizophrenia, non-affective psychosis and affective disorders by ICD 10 | 15 | Infection: hospital records | Mean: 29.3, SD 6.0 | CNS infection = 0.66% | Gender | 5 |
| CNS infection = 3599 (414 bacterial and 3185 viral) | Outcome: last discharge diagnosis from National Psychiatric Hospitalization Case Registry | Range: 20–50 years | CNS Viral = 0.56% | Strength: large sample | ||||
| Control = 6371 acute gastroenteritis | CNS Bacterial = 1.45% | Limitations: potential for bias as controls also suffered from an infectious illness, only used hospitalised cases of psychosis, short follow up | ||||||
| Controls = 0.75% | ||||||||
| Dalman et al. (2008) | Cohort study: | Schizophrenia and non-affective psychosis by ICD 9 and ICD 10 | 12 | Infection and psychosis: Swedish National Inpatient Register | Range: 17–29 years | CNS infection = 0.26%b | Age, gender, urbanicity, parental psychosis | 7 |
| CNS infection = 8985 (2435 bacterial and 6550 viral) | CNS Viral = 0.29%b | Strengths: large sample, adjusted for important confounders | ||||||
| Unexposed = 1,178,586 | CNS Bacterial = 0.16%b | Limitations: only used hospitalised cases of psychosis, short follow up, did not account for attrition and possibility of outcome at the time of exposure assessment. | ||||||
| Unexposed = 0.19%b | ||||||||
| Abrahao et al. (2005) | Case control: | Schizophrenia and other psychosis by ICD 10 | 4 | Infection: hospital records | Mean: 30, SD 5.9 | Meningitis = 4.21% | Unaffected siblings served as controls | 5 |
| Meningitis = 190 | Outcome: telephone directory search followed by interview with psychiatrist and neurological evaluation | Control = 0% | Strength: reliable assessment of outcome | |||||
| Control = 156 unexposed sibling | Limitation: small sample, high attrition and potential for selection bias | |||||||
| Koponen et al. (2004)c | Birth cohort: | Schizophrenia by DSM-III-R | 14 | Infection: hospital dmission and neurological outpatient clinic records | Mean: 31 | CNS infection = 2.75% | Social class, gender, perinatal brain damage, mental retardation, childhood epilepsy | 7 |
| CNS infection = 145 (102 viral) | Outcome: Finnish Hospital Discharge Register (FHDR) | CNS Viral = 3.92% | Strengths: large sample | |||||
| Unexposed = 10791 | CNS Bacterial = 0 | Limitations: only used hospitalised cases of psychosis | ||||||
| Unexposed = 0.88% | ||||||||
| Rantakallio et al. (1997) | Birth cohort: | Schizophrenia, other psychosisand schizophrenia spectrum disorder by DSM-III-R | 14 | Infection: hospital admission and neurological outpatient clinic records | Mean: 28 | CNS infection = 2.75% | Social class, gender, perinatal brain damage, mental retardation, epilepsy and hearing deficits | 7 |
| CNS infection = 145 (102 viral) | Outcome: Finnish Hospital Discharge Register | CNS Bacterial = 0 | Strengths: large sample | |||||
| Unexposed = 10872 | Unexposed = 0.66% | Limitations: only used hospitalised cases of psychosis | ||||||
| Suvisaari et al. (2003) | Cohort study: | Schizophrenia by ICD (8, 9 and 10) | 15 | Infection: laboratory records | Mean: 32, SD 4.5 | All CNS viral = 0.94% | – | 3 |
| CNS viral infections (n = 320) | Outcome: Finnish Hospital Discharge Register | Range: 23–41 years | Strength: reliable assessment of exposure | |||||
| Limitation: small sample, no control group used | ||||||||
| Leask et al. (2002) | Birth cohort: | Schizophrenia and affective psychosis by Present State Examination (PSE) and CATEGO | 11 | Infection: examination by school medical officer and interview with mother at age 11 years | Range: 16–28 years | Meningitis: | Gender and social class | 6 |
| Childhood infection = 74d | Outcome: National psychiatric hospital admission records | Schizophrenia group = 4.34% | Strength: large sample | |||||
| Unexposed = about 12,000 | Control group = 0.6% | Limitations: only used hospitalised cases of psychosis, some exposure information relied on maternal report |
a
New Castle–Ottawa Scale (NOS) score, higher score represents better quality (maximum score 9).
b
Non-affective psychosis including schizophrenia.
c
Based on 31 year follow of the 1966 Finnish birth cohort previously reported by Rantakallio et al.
d
Only study to include non-central nervous system infection in exposure; exposures included measles, chicken pox, mumps, German measles, whooping cough, scarlet fever, infectious hepatitis, rheumatic fever, meningitis and tuberculosis.