Objective Little is known about the psychological experiences of individuals being investigated for cardiac inherited diseases (CID). This study aimed to assess the prevalence, trajectory and associated variables of anxiety and depression in this population.Design This was a longitudinal study with 116 individuals being investigated for a CID; 85 (73%) completed follow-up.Main Outcome Measures Questionnaires were administered at the first appointment, post-disclosure of genetic results, and six-months later. Questionnaires measured demographic and psychological variables. The NZCID Registry provided clinical and genetic information.Results Thirty-seven (43%) individuals reported clinical and subclinical levels of anxiety and/or depression at least once. Anxiety and depression at follow up were associated with anxiety (p < .001) and depression (p < .001) at baseline. Elevated anxiety and depression scores at any point were also associated with more reporting of somatic symptoms (p < .001), poorer social support (p < .01) and greater intolerance for uncertainty (p < .001). There were five different trajectories of anxiety and depression: stable-low, stable-high, increasing, decreasing and fluctuating.Conclusion A significant minority of individuals being investigated for a CID experience anxiety and depression. Ongoing screening for anxiety, depression, social support and somatic symptoms could help identify those individuals.