Episodes of mass sociogenic illness are becoming increasingly recognised as a significant health and social problem that is more common than is presently reported.

To provide historical continuity with contemporary episodes of mass sociogenic illness in order to gain a broader transcultural and transhistorical understanding of this complex, protean phenomenon.

Literature survey to identify historical trends.

Mass sociogenic illness mirrors prominent social concerns, changing in relation to context and circumstance. Prior to 1900, reports are dominated by episodes of motor symptoms typified by dissociation, histrionics and psychomotor agitation incubated in an environment of preexisting tension. Twentieth-century reports feature anxiety symptoms that are triggered by sudden exposure to an anxiety-generating agent, most commonly an innocuous odour or food poisoning rumours. From the early 1980s to the present there has been an increasing presence of chemical and biological terrorism themes, climaxing in a sudden shift since the 11 September 2001 terrorist attacks in the USA.

A broad understanding of the history of mass sociogenic illness and a knowledge of episode characteristics are useful in the more rapid recognition and treatment of outbreaks.

Despite improvements in psychiatric teaching, British medical schools have never produced enough graduands aiming for psychiatry.

To inform the strategy for improving recruitment.

A literature review.

The number of psychiatrists required depends on the role of psychiatry, which is constantly changing. The present requirement is about 250–300 per year, including replacements and new posts. The number of psychiatric trainees has always been higher than expected from the career plans of newly qualified doctors, but the number of British graduates passing the Royal College of Psychiatrists' Membership examination has still fallen short, requiring a supplement of foreign medical graduates. The recent 50% expansion in medical students may make this country self-sufficient.

To improve recruitment, the College should focus on influences before and after undergraduate training – the kind of student entering medical school and the factors favouring sustained psychiatric practice after graduation.

Recovery in bipolar disorder is central to its definition but is rarely complete. Previous work has suggested that neuropsychological impairment persists during the euthymic state but has been confounded partly by mild affective symptoms in remitted patients.

To characterise neuropsychological functioning in the euthymic phase of bipolar disorder with an emphasis on tasks of executive functioning.

Thirty euthymic patients with bipolar disorder were compared with thirty healthy controls on neuropsychological tasks differentially sensitive to damage within prefrontal cortex.

Bipolar I patients were impaired on tasks of attentional set shifting, verbal memory and sustained attention. Only sustained attention deficit survived controlling for mild affective symptoms. This deficit was related to progression of illness, but was none the less present in a subgroup of patients near illness onset.

Sustained attention deficit may represent a neuropsychological vulnerability marker for bipolar disorder, providing a focus for further understanding of the phenotype and analysis of the neuronal networks involved.

Neurocognitive impairments in euthymic patients with bipolar disorder may represent trait rather than state variables.

To test the hypothesis that euthymic patients with bipolar disorder would exhibit impairment in verbal learning and memory and executive function compared with healthy controls matched for age, gender and premorbid IQ.

Twenty euthymic patients with bipolar disorder were matched, on a case-by-case basis, to twenty healthy community controls. Cases and controls were tested with a battery of neuropsychological tests.

Impairments were found in cases compared with controls in tests of verbal learning and memory. Verbal learning and memory correlated negatively with the number of manic episodes.

Impaired verbal learning and memory may be a trait variable in bipolar disease. There are implications for adherence to medication and relapse and for the role of early treatment interventions. Prospective designs and targeting first-episode groups may help to differentiate trait v. disease process effects.

Women who are positive for thyroid antibodies in early gestation are prone to post-partum depression, apparently independent of thyroid dysfunction, as measured by serum levels of free thyroxine, free triodothyroxine and thyroid-stimulating hormone. This finding may be due to infrequent monitoring of thyroid function, because hyperthyroidism, hypothyroidism and combinations of both may occur post-partum.

To test the hypothesis that stabilising thyroid function post-partum by administering daily thyroxine reduces the rate of occurrence and severity of associated depression.

In a randomised double-blind placebo-controlled trial, 100 of thyroxine or placebo was given daily to 446 thyroid-antibody-positive women (342 of whom were compliant) from 6 weeks to 6 month spost-partum, assessing their psychiatric and thyroid status at 4-weeklyintervals.

There was no evidence that thyroxine had any effect on the occurrence of depression. The 6-month period prevalence of depression was similar to that reported previously.

The excess of depression in thyroid-antibody-positive women in the post-partum period is not corrected by daily administration of thyroxine.

Claims that schizophrenia is a disease of the limbic system have been strengthened by meta-analyses of magnetic resonance imaging (MRI) studies finding reduced hippocampus and amygdala volumes. Some post-mortem studies do not find these abnormalities.

To assess the volume of the amygdala in a series of brains post-mortem.

Amygdala volume was estimated using point-counting in both hemispheres of the brains of 10 male and 8 female patients with schizophrenia, and a comparison group of 9 males and 9 females.

No significant reduction of amygdala volume was found.

Significant volume reduction of the amygdala is not a consistent feature of schizophrenia; findings from early MRI studies using coarse delineation methods may introduce bias to subsequent meta-analyses.

It is not clear how far brain abnormalities in early-onset schizophrenia result from progressive neurodevelopmental or neurodegenerative processes.

To investigate the hypothesis that structural brain abnormalities in adolescent-onset schizophrenia are progressive in the early phase of the illness.

A magnetic resonance imaging case–control study of 16 adolescents with schizophrenia (mean age 16.6 years, s.d.=1.9 years) with a meantime of 2.7 years (s.d.=1.7 years) between measurements and 16 matched controls (average age 16.0 years, s. d.=2.0 years) with a mean time of 1.7 years (s.d.=0.5 years) between measurements.

There was no evidence of progressive structural brain changes during late adolescence. Significant ventricular enlargement (greater in males) and left-sided temporal lobe changes were evident from the outset of the illness.

Neurodevelopmental brain abnormalities are non-progressive during late adolescence.

Many studies have found that people with schizophrenia exhibit abnormally high levels of semantic priming. Post-mortem and neuroimaging studies of schizophrenia suggest a reduction of neuritic processes (dendrites and synapses).

To demonstrate that reductions in neuritic processes can produce excessive priming in patients with schizophrenia.

Associative memory was simulated using a computer-based neural network system consisting of two interactive neural groups, one coding for individual memories and the other for the category to which each memory belonged.

Variation of a single parameter determining the density of local connections within the two neuronal groups gave a close approximation to levels of memory access and semantic priming previously reported in normal subjects and in patients with schizophrenia.

This study suggests that schizophrenia arises from excessive pruning of local connections in association cortex. Its findings shed light on the mechanisms underlying cognitive priming more generally, and how it might emerge developmentally.

Serious violence is an unusual but significant correlate of psychosis, and leads to the need for specialist secure psychiatric services. Most such service users have previously used general psychiatric services.

To examine diagnostic and socio-demographic differences between high-security psychiatric service users from their peers in community services.

Two groups of patients with psychosis were compared: a national sample of high-security hospital residents, and a sample of patients in contact with general psychiatric services.

Schizophrenia was the almost invariable diagnosis for all special hospital patients. White patients in the community sample were significantly more likely to have affective components to their illness compared with African–Caribbean patients; unlike those in special hospitals. There was a small excess in the proportion of African–Caribbean patients in the special hospital group, controlling for diagnosis, gender and locality. Men were overrepresented in this group.

Among patients with psychosis, having a diagnosis of schizophrenia and being male increase the likelihood of special hospital admission. Suggestions that ethnic minority patients are much more likely to have engaged in serious violence and need high-security placement were not borne out.

Obsessive–compulsive disorder has been reported in association with Prader–Willi syndrome.

To report the nature and prevalence of compulsive and similar symptoms associated with Prader–Willi syndrome in a population ascertained as completely as possible.

Attempted complete ascertainment of people with Prader– Willi syndrome in eight English counties. Administration of standardised rating scales and a structured interview. Comparison with people with learning disability and high body mass indices.

Prader–Willi syndrome was associated with high rates of ritualistic behaviours, such as the need to ask or to tell something, insistence on routines, hoarding and ordering objects and repetitive actions and speech, compared with the control group, and was negatively correlated with IQ and socialisation age. Typical obsessive–compulsive symptoms, such as checking, counting and cleaning compulsions or obsessional thoughts, were not found.

Ritualistic and compulsive behaviours occur more frequently in association with Prader–Willi syndrome than among people with intellectual disability and significant obesity.

Dissociative symptoms during trauma predict post-traumatic stress disorder (PTSD), but they are often transient. It is controversial whether they predict chronic PTSD over and above what can be predicted from other post-trauma symptoms.

To investigate prospectively the relationship between dissociative symptoms before, during and after a trauma and other psychological predictors, and chronic PTSD.

Two samples of 27 and 176 road traffic accident survivors were recruited. Patients were assessed shortly after the accident and followed at intervals over the next 6 months. Assessments included measures of dissociation, memory fragmentation, data-driven processing, rumination and PTSD symptoms.

All measures of dissociation, particularly persistent dissociation 4 weeks after the accident, predicted chronic PTSD severity at 6 months. Dissociative symptoms predicted subsequent PTSD over and above the other PTSD symptom clusters. Memory fragmentation and data-driven processing also predicted PTSD. Rumination about the accident was among the strongest predictors of subsequent PTSD symptoms.

Persistent dissociation and rumination 4 weeks after trauma are more useful in identifying those patients who are likely to develop chronic PTSD than initial reactions.

Numbers of immigrant elders are increasing and it is unclear whether they can access services.

To examine service utilisation of older immigrants compared with their UK-born counterparts and relate it to health difficulties.

Cross-sectional study in inner London measuring service use, mental health and disability.

A total of 1085 people aged ⩾65 years were interviewed. Independent predictors of contact with a general practitioner included being born in Cyprus. Cypriots were the only immigrant population to report significantly more somatic symptoms than those born in the UK (P=0.005). Africans and Caribbeans used daycare and other social services most frequently.

Immigrants could access services. Africans and Caribbeans appear to have poorer physical health and thus have greater contact with services. Cypriots who experience depression may present with prominent somatic symptoms. This is likely to be due to a different idiom of distress.

War pensions are used to examine different models of psychological understanding. The First World War is said to have been the first conflict for which pensions were widely granted for psychological disorders as distinct from functional, somatic syndromes. In 1939 official attitudes hardened and it is commonly stated that few pensions were awarded for post-combat syndromes.

To re-evaluate the recognition of psychiatric disorders by the war pension authorities.

Official statistics were compared with samples of war pension files from the Boer War and the First and Second World Wars.

Official reports tended to overestimate the number of awards. Although government figures suggested that the proportion of neurological and psychiatric pensions was higher after the Second World War, our analysis suggests that the rates may not have been significantly different.

The acceptance of psychological disorders was a response to cultural shifts, advances in psychiatric knowledge and the exigencies of war. Changing explanations were both a consequence of these forces and themselves agents of change.