Comparative study of clinical and neuropsychological characteristics between early-, late and very-late-onset schizophrenia-spectrum disorders.

Objective: To compare the clinical and neurocognitive profile of early-onset (EOP, <40 years), late-onset (LOP, 40-59 years) and very-late-onset (VLOP, ≥60 years) psychosis.

Design: Cross-sectional observational study.

Setting: Secondary, tertiary, and community mental health care.

Subjective experience of cognitive failures as possible risk factor for negative symptoms of psychosis in the general population.

Objective: The aim of this study was to examine whether proneness to subjective cognitive failure (cognitive based mistakes) increases the risk for the development of symptoms of psychosis and to what degree any association was familial.

Methods: At baseline, the Cognitive Failure Questionnaire (CFQ) and the Community Assessment of Psychic Experiences (CAPE) questionnaire were administered in a general population sample of genetically related individuals (n = 755). Individuals scoring high (>75th percentile) or average on the CAPE (between 40th and 60th percentile) (n = 488) were reinterviewed with the CAPE and Structured Interview for Schizotypy-Revised (SIS-R) at follow-up (mean interval = 7.

Role of distress in delusion formation.

Background: Contemporary cognitive psychological theories suggest that distress plays a mediating role in delusion formation.

Aims: To study the amplifying role of distress from early perceptual intrusions to delusion formation.

Method: A general population sample of 7076 individuals was interviewed with the Composite International Diagnostic Interview (CIDI) in 1996 (baseline), 1997 (T1) and 1999 (T2).

The incidence and outcome of subclinical psychotic experiences in the general population.

Objectives: To examine the incidence and 2-year stability and outcome of subclinical psychotic experiences in the general population.

Design: The Netherlands Mental Health Survey and Incidence Study (NEMESIS), a longitudinal general population study.

Methods: A representative population sample of 7,076 participants was interviewed with the composite international diagnostic interview at baseline, 1 year later at T(1) and again 2 years later at T(2).

Development of depressed mood predicts onset of psychotic disorder in individuals who report hallucinatory experiences.

Objectives: Current psychological theories state that the clinical outcome of hallucinatory experiences is dependent on the degree of associated distress, anxiety, and depression. This study examined the hypothesis that the risk for onset of psychotic disorder in individuals with self-reported hallucinatory experiences would be higher in those who subsequently developed depressed mood than in those who did not.

Design: A prospective cohort study of a general population sample.

Familial covariation of the subclinical psychosis phenotype and verbal fluency in the general population.

Objective: Cognitive impairments may be markers of familial transmission of liability to psychosis. This study examined to what degree the subclinical psychosis phenotype in the general population shows similar familial continuity with cognition, measured with a verbal fluency test, and whether this was similar for men and women.

Methods: Measures of the subclinical psychosis phenotype and verbal fluency were administered to a general population sample of genetically related individuals (n=425).

When does experience of psychosis result in a need for care? A prospective general population study.

Not all individuals with experience of psychosis develop a need for care. The present study investigated differences in coping strategies and associated levels of perceived control over psychotic symptoms, in relation to need for care status. The influence of coping on need for care was assessed in 47 individuals incident for psychosis in a general population sample of 4,722.

Do urbanicity and familial liability coparticipate in causing psychosis?

Objective: The urban environment and familial liability are risk factors for psychotic illness, but it is not known whether a biological synergism exists between these two proxy causes.

Method: The amount of biological synergism between familial liability (defined as a family history of delusions and/or hallucinations necessitating psychiatric treatment) and a five-level rating of population density of place of residence was estimated from the additive statistical interaction in a general population risk set of 5,550 individuals.

Results: Both the level of urbanicity (adjusted summary odds ratio=1.

Does the urban environment independently increase the risk for both negative and positive features of psychosis?

Background: Psychotic disorders are more common in urban environments. It is not known whether the increase in risk applies to both the positive and negative dimensions of psychosis.

Methods: In a random general population sample of 7076, measures of positive and negative symptoms of psychosis were constructed using Composite International Diagnostic Interview (CIDI) data.