Auditory verbal hallucinations are conceptualised as hearing voices or a sense of being communicated to without any external speaker present. Historically viewed as hallmarks of psychosis and other serious mental illnesses, we now know that nonclinical voices can occur with varying intensities and frequencies in the general population too. However, clinical voices such as those of a commanding nature often contribute to severe levels of distress and dysfunction, especially when the voices command the voice-hearer to carry out harmful actions against their will. Related phenomena, called delusions of (thought) interference, include thought insertion and delusion of control, defined as the feeling that someone external is sending or forcing thoughts into a person's mind and being under the influence of an external power, respectively. Command hallucinations, delusion of control and thought insertion breach if not erase the boundary between one's self and other, thus leading to a confusion between internal and external events which can make the commands exceedingly difficult to resist. Sometimes both the distress caused by and the coercive nature of such experiences can lead to suicidal feelings and behaviours including acts of self-harm. This project aims to investigate the relationships between such command hallucinations, inserted thoughts and suicidal behaviours by studying their trajectories, how they develop and change over time, as well as clarifying the impact of these experiences on individuals' mental wellbeing versus diagnoses of mental illness.