The COVID-19 pandemic and mitigation measures are likely to have a marked effect on mental health. It is important to use longitudinal data to improve inferences.

To quantify the prevalence of depression, anxiety and mental well-being before and during the COVID-19 pandemic. Also, to identify groups at risk of depression and/or anxiety during the pandemic.

Data were from the Avon Longitudinal Study of Parents and Children (ALSPAC) index generation (n = 2850, mean age 28 years) and parent generation (n = 3720, mean age 59 years), and Generation Scotland (n = 4233, mean age 59 years). Depression was measured with the Short Mood and Feelings Questionnaire in ALSPAC and the Patient Health Questionnaire-9 in Generation Scotland. Anxiety and mental well-being were measured with the Generalised Anxiety Disorder Assessment-7 and the Short Warwick Edinburgh Mental Wellbeing Scale.

Depression during the pandemic was similar to pre-pandemic levels in the ALSPAC index generation, but those experiencing anxiety had almost doubled, at 24% (95% CI 23–26%) compared with a pre-pandemic level of 13% (95% CI 12–14%). In both studies, anxiety and depression during the pandemic was greater in younger members, women, those with pre-existing mental/physical health conditions and individuals in socioeconomic adversity, even when controlling for pre-pandemic anxiety and depression.

These results provide evidence for increased anxiety in young people that is coincident with the pandemic. Specific groups are at elevated risk of depression and anxiety during the COVID-19 pandemic. This is important for planning current mental health provisions and for long-term impact beyond this pandemic.

Drawing a distinction between cortical and subcortical dementias seems both useful and justified. Recent research has, however, cast doubt on the clinical, neuropsychological, neuroimaging and neuroanatomical basis of the distinction.

To arrive at a reasoned conclusion about the relationship between the two types of dementia and the validity of distinguishing between them.

The historical and recent clinical and scientific literature on subcortical dementia was reviewed.

The traditional claim that subcortical dementia has distinct clinical manifestations, neuroimaging findings and a neuropathological profile is not altogether borne out by the literature. Some studies show that frontal executive dysfunction and the profile of memory deficits are not significantly different from those seen in Alzheimer's disease. Neuropathological findings also overlap.

The category of subcortical dementia may be clinically useful in highlighting the likelihood that an individual with dementia is more likely to suffer from bradyphrenia and motor difficulties. As neuroscience advances a preoccupation with the distinction may hinder the assessment and treatment of individual cases.