Acceptance and Commitment Therapy in Tuberous Sclerosis Complex

Inclusion Criteria: * Aged 11 to 24 years. * Diagnosis of Tuberous Sclerosis Complex. * Sufficient understanding of English to engage with the intervention (spoken and written), as judged by the assessing clinician. * Sufficient cognitive, sensory and speech capabilities to take part in the intervention. * Participants (or their parents if under 16) give verbal or written informed consent to participate in the study. * Participants give verbal or written assent if under 16. * Receiving treatment over video-conferencing will be the default modality for delivery, so access to the internet is a requirement. Exclusion Criteria: * Previous structured behavioural intervention within last 6 months. * Previous or current alcohol/substance dependence, psychosis, suicidality, or anorexia nervosa. * Moderate or severe intellectual disability. * Immediate risk to self or others. * Parent or child not able to speak, read or write English.