Alexithymia in autism: cross-sectional and longitudinal associations with social-communication difficulties, anxiety and depression symptoms

Background: Alexithymia (difficulties identifying and describing emotion) is a transdiagnostic trait implicated in social-emotional and mental health problems in the general population. Many autistic individuals experience significant social-communication difficulties and elevated anxiety/ depression and alexithymia. Nevertheless, the role of alexithymia in explaining individual variability in the quality/ severity of social-communication difficulties and/ or anxiety and depression symptoms in autism remains poorly understood. Methods: 337 adolescents and adults (autism N=179) were assessed for alexithymia on the Toronto Alexithymia Scale and for social-communication difficulties, anxiety and depression symptoms. 135 individuals (autism N=76) were followed up 12-24-months later. We used regression models to establish cross-sectional and longitudinal associations between alexithymia, social-communication difficulties, anxiety and depression symptoms. Results: Autistic individuals reported significantly higher alexithymia than comparison individuals (p<0.001, r effect size=0.48), with 47.3% of autistic females and 21.0% of autistic males meeting cut-off for clinically relevant alexithymia (score ≥61). Difficulties describing feelings were particularly associated with current self-reported social-communication difficulties (p<0.001, β=0.57, 95% CI [0.44, 0.67]) and predicted later social-communication difficulties (p=0.02, β=0.43, 95% CI [0.07, 0.82]). Difficulties identifying feelings were particularly associated with current anxiety symptom severity (p