Examining the pathway to self-harm in high-risk youth using a novel Card Sort Task for Self-Harm (CaTS): It’s time to change how self-harm is assessed

By Katherine Bird.

Self-harm (any self-injury or -poisoning regardless of intent) is a significant public-health concern, affecting between 18.8% and 50% of young people under 25-years [1; 2]. The concern relates to the physical harm, emotional distress, and reduced mental health and wellbeing self-harm causes. Most concerningly, self-harm is the most significant predictor of death by suicide. Two youth groups are at particularly high risk of self-harm and suicidality: Trans youth and young people with disordered eating (DE). Approximately half of trans people will self-harm at least once [3]. Self-harm and DE are highly comorbid and simultaneously experiencing both reduces mental health outcomes and increases the risk of death by suicide [4]. Considering this, addressing self-harm in these high-risk youth groups is key to reducing later suicide risk and improving health and wellbeing outcomes.

Each high-risk youth group experiences both group-specific and general risk factors for self-harm. These include depression, impulsivity, abuse, and relationship difficulties. Historically, self-harm risk factors have been investigated in isolation, or with one other factor. This limits the predictive value of risk assessments and the effectiveness of subsequent interventions, as focus is placed on single key risk factors while ignoring other risk and protective factors a person experiences on their self-harm pathway. The complex dynamics between multiple factors is not understood. Further, little is understood about what occurs when someone considers but does not proceed to self-harm, or when someone chooses to engage in an alternative behaviour (i.e., reading, speaking to a friend, binge-drinking) in lieu of self-harm. I have three large-scale online studies planned to investigate these gaps in knowledge during my PhD using a novel card sort task for self-harm (CaTS).

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Rather than focus on single risk factors CaTS uses 117-cards with thoughts, feelings, events, and behaviours, identified by previous research as being factors associated with self-harm, to examine the temporal dynamics between multiple factors. Young people can describe their personal pathway to self-harm along a 6-month timeline by placing personally relevant cards at the timepoint they occurred. During my PhD, I will first develop an online version of CaTS to address the identified gaps in knowledge. The first study will investigate the pathway to self-harm in each high-risk youth group. The second study will examine transitions between factors when a person considers but does not engage in self-harm. Finally, a study will examine transitions between factors when young people consider self-harm but engage in alternative behaviours. Lag-sequential analysis and Indicator Wave Analysis will be used to examine the temporal dynamics between multiple risk and protective factors. These methods of analysis will allow me to determine how and when frequently occurring sequences of factors occur along each groups self-harm pathway. This will identify factors (both antecedents and consequences) of self-harm episodes for each high-risk group, thus offering group-specific targets for intervention. Mapping factorial changes over time identifies causal effects and can be used to predict future behavioural pathways and outcomes [5].

Ultimately, the intention is that CaTS will be a useful clinical tool to help the client and clinician better understand client’s personal self-harm pathway and identify meaningful intervenable targets for that person. Understanding the complex dynamics between multiple factors experienced on the pathway to self-harm is essential to appropriately addressing self-harm, reducing suicide risk, and improving the health and wellbeing outcomes for high-risk youth groups.


  1. Kidger, J., Heron, J., Lewis, G., Evans, J., & Gunnell, D. (2012). Adolescent self-harm and suicidal thoughts in the ALSPAC cohort: a self-report survey in England. BMC Psychiatry, 12(1), 1-12
  2. Junker, A., Nordahl, H. M, Bjørngaard, J. H., & Bjerkkeset, O. (2019). Adolescent personality traits, low self-esteem and self-harm hospitalisation: a 15-year follow-up of the Norwegian young-HUNT1 cohort. European Child and Adolescent Psychiatry, 28(3), 329-339
  3. Taliaferro, L. A., McMorris, B. J., Rider, G. N., & Eisenberg, M. E. (2019). Risk and protective factors for self-harm in a population-based sample of transgender youth. Archives of Suicide Research, 23(2), 203-221
  4. Erlangsen, A., Banks, E., Joshy, G., Calear, A. L., Welsh, J., Batterham, P. J., & Salvador-Carulla, L. (2021). Measures of mental, physical, and social wellbeing and their association with death by suicide and self-harm in a cohort of 266, 324 persons aged 45 years and over. Social Psychiatry and Psychiatric, 56(2), 295-303
  5. Keatley, D., & Clarke, D. (2018). Indicator Waves: a new temporal method for measuring multiple behaviours as indicators for future events. Measuring Behaviour, 92-95

Katherine Bird (@BirdKatherine) is currently a PhD student at the University of Nottingham. Her PhD investigates self-harm and suicide ideation in vulnerable populations. Email: