Inclusion Criteria:  All participants must be 18 years of age or older. Participants must have a clinical diagnosis of stroke or brain injury Must be able to understand English and communicate responses The target participant has been referred to the adapted ACT group by a clinician, stroke association co-ordinator or senior Headway professional. Participants with a mild to moderate level of psychological need Participants must be capable of giving informed consent  Exclusion Criteria:  Candidates with significant cognitive/language/behavioural impairment that would prevent them from engaging with the group Candidates with a diagnosed degenerative condition (e.g. dementia). (NB candidates with a brain tumour diagnosis who are currently stable will be eligible.) Candidates experiencing severe/active psychotic symptoms Candidates with a high level of psychological need that would be better met through a more intensive intervention Candidates receiving other therapies, as part of a multi-component intervention that would prevent any changes specific to the group psychotherapy to be estimated (except drugs for depression and anxiety)