The Suicidal Ideation Attributes Scale-Modified (SIDAS-M): Development and preliminary validation of a new scale for the measurement of suicidal ideation in autistic adults

Abstract

The study describes the development and preliminary psychometric validation of the Suicidal Ideation Attributes Scale-Modified (SIDAS-M), a five-item assessment of suicidal ideation for use with autistic adults. Participants ( n = 102 autistic adults; 58% women, 34% men, 8% nonbinary; Mage = 41.75, SD = 12.89) completed an online survey including the SIDAS-M at Time 1 and participated in follow-up interviews at Time 2 (~111 days later). A single factor solution provided good to excellent fit to the data (comparative fit index = 0.961, Tucker–Lewis index = 0.921; standardized root mean square residual = 0.027), with all items showing good to excellent loadings (0.74–0.91). SIDAS-M total score (ω=.930, bias-corrected and accelerated 95% confidence interval (BCa 95% CI) [.90, .95]) demonstrated good convergent validity, correlating significantly with existing suicide specific (ρ=.442–.698, p<.001) and well-being measures (ρ=.325.–.505, p≤.001), and good divergent validity. Logistic regression controlling for age, gender, and relationship status indicated that SIDAS-M scores at Time 1 significantly predicted suicidal behavior at Time 2, β = 0.462, p < 0.001, [0.032, 0.068]. Receiver operating characteristic curve analysis indicated SIDAS-M has utility discriminating between participants classified at low or above low risk, area under the curve = 0.866, [0.767, 0.966], p < 0.001, with a cutoff score ⩾1 providing a potentially useful indicator of increased suicidal risk. Overall, SIDAS-M demonstrated good psychometric properties when used with autistic adults without intellectual disability. Lay Abstract Autistic people may be at higher risk of suicidal behavior than people in the general population. Suicidal behavior may include thinking about suicide or attempting to end one’s own life by suicide. It is important to identify autistic people who may be thinking about suicide. People who are at risk of suicidal behavior can be identified by asking questions about whether they have been thinking about suicide. A specially designed questionnaire, or screening instrument, can help someone ask the best questions to find out if someone has been thinking about suicide. This information can help to identify supports to be put in place to prevent suicidal behavior, such as a suicide attempt. However, autistic people may interpret questions differently than non-autistic people. It is important to use screening tools that have been designed with, and for autistic people. In this study, we examined the Suicidal Ideation Attributes Scale (SIDAS). The SIDAS is an existing tool that was developed to screen for suicidal thinking in the general population. We modified SIDAS for use with autistic adults. We involved autistic people in the process of modifying SIDAS. We called the modified instrument the SIDAS-M. The results of our study showed SIDAS-M may be useful for screening for suicidal thinking in autistic adults who do not have an intellectual disability.

The role of anxiety and depression in suicidal thoughts for autistic and non‐autistic people: A theory‐driven network analysis

“…This study is limited by an absence of valid measurement tools to explore suicidal thoughts and behaviors for autistic people at the time of design. Researchers should consider using the recently published Suicidal Behaviours Questionnaire‐Revised (Autism Spectrum Condition) (SBQ‐ASC) (Cassidy, Bradley, Cogger‐Ward, & Rodgers, 2021 ) or the Suicidal Ideation Attributes Scale‐Modified (SIDAS‐M) (Hedley et al, 2022 ). This study used self‐report autism diagnosis, which falls short of “gold standard” confirmation of autism but allows for wider participation.…”

The effectiveness and safety of dialectical behavior therapy for suicidal ideation and behavior in autistic adults: a pragmatic randomized controlled trial

“…At the study's outset, the SIDAS lacked validation for autism samples. In 2023, the SIDAS-M was developed and validated for this purpose, incorporating language revisions and visual analog scales (Hedley et al, 2023). However, the SIDAS was conducted as an interview, not a selfreport questionnaire, in the current study.…”

Autism and Suicide: Strategies to Dovetail Emerging Evidence in Child and Adolescent Suicide Risk Assessments

“…The same research group proposed that items/questions in self-report suicidal scales need to be speci cally designed for ASD individuals due to differences in the theory of the mind and language delays or skills (Pelton et al, 2020). The Suicidal Ideation Attributes Scale-Modi ed (SIDAS-M) is a newer tool being developed in Australia, speci cally for the measurement of STB in autistic adults (Hedley et al, 2022). Similarly, the self-report scales of Interpersonal Theory of Suicide (ITS) have shown some mixed results due to differences in measurement properties and may need some modi cations to explore the role of its constructs in the development of STB in individuals with ASD.…”