Turner Syndrome (45,X; TS) is one of the most common sex chromosome aneuploidies. It is associated with physical morbidities affecting nearly every body system, but there has been little research into the psychological wellbeing of girls, adolescents and young women with TS (Chapter 1). We conducted a large online mental health survey with TS participants aged 4 to 25. This showed they had elevated rates of mental health disorder and social skills difficulties compared to typically developing females (Chapter 2). 33% of participants met criteria for at least one DSM-5 mental health diagnosis. Of these, 23% met criteria for an autism spectrum disorder, 11% had anxiety disorders and 13% had an attention deficit hyperactivity disorder. Nearly two-thirds (59%) had autistic-like social communication difficulties of clinical significance. We hypothesized that those social communication difficulties could be improved with a social skills intervention. First, we reviewed the published evidence for the effectiveness of appropriate treatment procedures. A subsequent meta-analysis identified PEERS as the best evidenced intervention (Chapter 3 and 4). Second, we conducted semi-structured interviews with young women with TS and their parents to assess the feasibility and acceptability of piloting PEERS. TS is rare and participants resided across the British Isles, therefore PEERS was not considered to be feasible in its original weekly face-to-face format (Chapter 5). Accordingly, the protocol was adapted to incorporate a novel online component which substituted for face-to-face meetings. This modification proved to be feasible and it was acceptable to families. Parents reported that their daughters had shown significant improvements in their social knowledge and performance after the two month intervention period. This improvement was sustained during a three month follow-up (Chapter 6)
