Recurrent microdeletions and microduplications of a 600 kb genomic region of chromosome 16p11.2 have been implicated in childhood-onset developmental disorders1-3. Here we report the strong association of 16p11.2 microduplications with schizophrenia in two large cohorts. In the primary sample, the microduplication was detected in 12/1906 (0.63%) cases and 1/3971 (0.03%) controls (P=1.2×10-5, OR=25.8). In the replication sample, the microduplication was detected in 9/2645 (0.34%) cases and 1/2420 (0.04%) controls (P=0.022, OR=8.3). For the series combined, microduplication of 16p11.2 was associated with 14.5-fold increased risk of schizophrenia (95% C.I. [3.3, 62]). A meta-analysis of multiple psychiatric disorders showed a significant association of the microduplication with schizophrenia, bipolar disorder and autism. The reciprocal microdeletion was associated only with autism and developmental disorders. Analysis of patient clinical data showed that head circumference was significantly larger in patients with the microdeletion compared with patients with the microduplication (P = 0.0007). Our results suggest that the microduplication of 16p11.2 confers substantial risk for schizophrenia and other psychiatric disorders, whereas the reciprocal microdeletion is associated with contrasting clinical features.

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The two-syndrome concept postulates two "dimensions of pathology" underlying schizophrenia--a reversible (and potentially neuroleptic-responsive) component and a sometimes progressive and relatively irreversible component associated with the deficit state and poor long-term outcome. Negative symptoms (narrowly defined) appear to be more closely associated with the latter component (the type II syndrome), as also are cognitive impairments, abnormal involuntary movements, and behavioral deterioration. This syndrome is assumed to be more closely related than the type I syndrome of positive symptoms to the structural brain changes inferred from pneumoencephalograms, computed tomography scans, and recent post-mortem studies. However, since both syndromes often occur in the same patient--sometimes at the same point in time--they presumably have the same etiology.

probably been the acceptability of myalgic encephalomyelitis as a diagnosis. Fatigue scores in our study were strongly correlated with depression scores, and a recent prospective study in general practice has confirmed this relation. 18 Depression as a cause of fibromyalgia is a much debated issue. Persistent pain is a depressing experience. Our finding that the depression score rises with tender point count irrespective of pain status, however, suggests that depression and fatigue may play a part in the genesis of tender points. This fits with the theory ofthe central modulation ofpain experience. Design-Subjects in a prospectively followed up cohort (the national child development study) who had been admitted as adults to psychiatric hospitals were compared with the rest ofthe cohort on ratings of social behaviour made by teachers at the ages of 7 and 11 years. CONCLUSIONSSubjects-40 adult patients with schizophrenic illnesses, 35 with affective psychoses, and 79 with neurotic illness who had been admitted for psychiatric reasons by the age of 28. 1914 randomly selected members of the cohort who had never been admitted for psychiatric treatment.Main outcome measures-Overall scores and scores for overreaction (externalising behaviour) and underreaction (internalising behaviour) with the Bristol social adjustment guide at ages 7 and 11.Results-At the age of 7 children. who developed schizophrenia were rated by their teachers as manifesting more social maladjustment than. controls (overall score 4 3' (SD 24) Av 3-1 (2*0; P