Attention-Deficit/Hyperactivity Disorder (ADHD) is characterised by symptoms of hyperactivity, impulsivity and attentional difficulties. Originally thought to be a condition of childhood, ADHD has now been recognised in adults. One of the main theoretical explanations of ADHD is related to deficits in Executive Functioning (EF). The state of current knowledge regarding the relationship between EF and ADHD was reviewed. Findings suggest that adults with ADHD are likely to exhibit deficits in EF mainly related to response inhibition, set-shifting or working memory. Deficits in EF as shown on neuropsychological tests may help to identify people who are at risk of under achieving in various life domains such as education or occupation. Tests of EF which are more ecologically valid may be more sensitive to EF dysfunction than traditional measures. The experience of having adult ADHD and preferences for support were explored using Interpretative Phenomenological Analysis (IPA). Four super- ordinate themes emerged from five interviews: 'Process of adapting to ADHD', 'Social Appraisal', 'Self-regulation' and 'Coping'. Participants described an adjustment process which impacted on their identity and the impact on self-perception was evident. ADHD was not understood well by others and some participants experienced stigma and bullying. A range of coping strategies were identified and clinical implications and limitations of the study were discussed. Finally, a commentary and reflexive analysis of the research process was offered and factors influential to the research were discussed.

Species relationships of the endemic Elaphoglossum, and the extent and distribution of population genetic diversity were investigated using allozyme analysis in chapter five. As well as supporting the relationships of the taxa in the molecular phylogeny, the allozyme data suggest a hybrid origin of E. dimorphum between E. nervosum and E. bfurcatum. In addition the allozyme data revealed significant genetic differentiation in populations of E. nervosum and E. bfurcatum which should be taken into consideration in any future conservation programme. To conclude, Chapter 5 is a general discussion on the evolution and conservation of island plants, highlighting my research findings from St Helena and comparing it to other studies.