Having two systems of psychiatric diagnosis creates unnecessary confusion therefore it would be desirable to achieve increased consistency between ICD-11 and DSM-5. Unfortunately, however, DSM-5 has included many controversial suggestions that have weak scientific support and insufficient risk–benefit analysis. As a result ICD-11 should learn from the DSM-5 mistakes rather than repeating them.

Although translational medicine has become a priority for medical science, advances in neuroscience have failed to be translated for the benefit of patients. In populations at high risk of psychosis, neuroimaging could stratify those mostly likely to develop psychosis. This is an example of potentially translatable psychiatry.

Larsson et al provide epidemiological evidence for a genetic association between attention-deficit hyperactivity disorder (ADHD) and both bipolar disorder and schizophrenia and Hamshere and colleagues confirm the latter association with genome-wide data. Although a genetic link between ADHD and bipolar disorder has been hypothesised for over a decade, the association with schizophrenia fills a notable gap in the literature. This editorial discusses the implications of these findings for clinicians, who must address psychiatric comorbidity in their treatment formulations, and researchers who are learning that the discrete categorical diagnoses of our diagnostic systems may not be up to the task of clarifying the causes and cures of psychopathology.

A young gentlewoman of the parish of Clifton … had hysterics … which … deprived her of … memory and understanding, and … continued for a considerable time, notwithstanding the best advice of two eminent physicians. In this melancholic state she was brought to Worcester, to try the effect of electricity … As the head was the part affected, I guided the fire chiefly to that part, in as plentiful a manner as I well could, and caused it to pass quite through several times each day, so long as she stayed in town, so though scarce a week, yet it seemed to have the desired effect; for although, before she came to Worcester, she could not remember half an hour to an end, yet, soon after her return home, she could remember most remarkable things she saw done in Worcester; and not only her memory, but her understanding also returned, and she very soon became perfectly well. The operation was sometimes shocks, sometimes drawing off sparks from the head.

Schizophrenia is characterised by generalised cognitive impairment that is both a risk factor and a predictor of outcome. Recent research into human intelligence supports the view that, in schizophrenia, poor performance on disparate cognitive tasks can be explained by dysfunction of a frontoparietal neural network thought to support fluid intelligence.

In mid-19th-century Germany the conviction that ‘mental disease is brain disease’ was accompanied by a call for social reform in psychiatry. During neurology training, future psychiatrists often encounter patients with mental disorders rarely seen in psychiatric departments and learn how to avoid misdiagnosing brain diseases as mental disorders.

The DSM system has never acknowledged a central position for mixed states; thus, mixed depressions have been almost completely neglected for decades. Now, DSM-5 is proposing diagnostic criteria for depression with mixed features that will lead to more misdiagnosis and inadequate treatment of this syndrome. Different criteria, based on empirically stronger evidence than exists for the DSM-5 criteria, should be adopted.

Despite rigorous research into the genetics of neuropsychiatric disorders, the mechanism by which polygenic risk leads to complex clinical phenotypes remains unclear. The Encyclopedia of DNA Elements (ENCODE) project gives us new insight into gene regulation, and gene–gene and gene–environment interaction.

Better understanding of these key genomic mechanisms may provide the answers we have been searching for.