The rate of suicide is significantly higher in adults with childhood ADHD compared with those without ADHD (standardised mortality rate, 4.83 [95% confidence interval, 1.14‒20.46]; p=0.032) (Barbaresi WJ et al, 2013). This study aimed to determine the presence of suicidal ideation and behaviours in adults with ADHD and examine the relationship between ADHD, affective temperaments, the presence of hypomania symptoms and the risk for suicide.
Participants (aged 18‒65 years) with ADHD, as determined by the Diagnostic and Statistical Manual for Mental Disorders – Fifth Edition (DSM-5TM) were inpatients at the General Psychiatry Clinic of Bolzano Hospital, Italy, in 2017. The control cohort were students and healthcare professionals working at the hospital with no psychiatric diagnoses. All participants were administered the Wender Utah Rating Scale (WURS), the Hypomania Check-List-32 (HCL-32), the Mood Disorder Questionnaire (MDQ), the Temperament Evaluation for Memphis, Pisa, Paris and San Diego (TEMPS-A) and the Columbia-Suicide Severity Rating Scale (C-SSRS).* Clinical information regarding ADHD diagnoses and sociodemographic information were retrieved from medical records for individuals with ADHD.
A total of 63 individuals with ADHD participated in the study (71.4% male; mean [standard deviation, SD] age, 36.78 [11.55] years); 69 participants (31.9% male; mean [SD] age, 42.39 [10.19] years) were included in the control cohort. The majority of participants in the ADHD and control cohort were Italian (60.3% and 58.8%, respectively), and the rest were German (39.7% and 41.2%, respectively). Combined-type ADHD was most prevalent in the ADHD cohort (73.0%), followed by hyperactive/impulsive type (15.9%) and inattentive type (11.1%). In the ADHD cohort, 46.0% had a DSM-5TM Axis 1 disorder: dysthymia (12.7%), bipolar disorder Type II (7.9%), bipolar disorder Type I (4.8%), cyclothymia (1.6%) or other specified disorders, such as anxiety disorder, post-traumatic stress disorder or substance abuse (27.0%). Axis 2 personality disorder as diagnosed by the Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV-TR) was present for 23.8% of individuals with ADHD. The presence of comorbid Axis 1 disorders (50.0% versus 57.1%; p=0.95) and personality disorders (20.0% versus 28.6%; p=0.92) were comparable between individuals with hyperactive/impulsive ADHD and inattentive ADHD.
Individuals with ADHD more often reported suicidal ideation compared with the control cohort (46.0% versus 5.9%; p<0.001); however, only 4.8% of those with ADHD reported active suicidal ideation with the intent to die and a specific plan. Actual suicide attempts were significantly higher for the ADHD cohort (9.5%) compared with the control cohort (0.0%; p=0.02). Preparatory acts or behaviours and interrupted suicide attempts and reported self-injurious behaviours without suicide intent were also higher for individuals with ADHD (20.6% and 15.9%, respectively; p=0.005) versus those without ADHD (0.0% and 3.8%, respectively; p=0.033).
Both cohorts differed on all administered scales, except for TEMPS-A Hyperthymia (p=0.22). Individuals with ADHD also had higher scores for all negative affective temperaments, HCL-32 and MDQ compared with the control cohort. Those with ADHD were more likely to have higher scores in their negative temperament/hypomania factors compared with the control cohort (odds ratio [standard error], 14.6 [0.53]; p<0.001). In this study, although the ADHD cohort were more likely to be male (odds ratio [SE], 7.92 [0.62]; p=0.001), this was not independently associated with suicidal ideation (odds ratio [SE], 3.71 [0.85]; p=0.12).
The first limitation of this study was the modest sample size and that all assessments were based on self-report questionnaires and not through direct observation of actual behaviours or any diagnostic interviews performed by a clinician, except suicidality. Using observations and interviews may have provided more accurate and reliable information. Additionally, due to the cross-sectional study design, definitive conclusions cannot be drawn regarding the cause–effect relationship between variables, and changes over time were not considered.
To conclude, a high incidence of suicidal ideation, comorbid psychiatric disorders and negative affective temperaments were reported in adults with ADHD. This highlights that the risk factors for suicide among individuals with ADHD should be regularly assessed by clinicians.
*The WURS is a 61-item self-report instrument to measure the presence, frequency and severity of ADHD symptoms experienced in childhood. The HCL-32 is a 32-item self-report scale for the evaluation of emotions, behaviours or thoughts linked to hypomanic symptoms. The MDQ is a 13-item self-report questionnaire to screen for hypomania or mania, with a final item measuring the level of impairment due to symptoms. The TEMPS-A is a 110-item self-report instrument to measure affective temperament traits. The C-SSRS is a semi-structured interview to assess suicidal ideation (intensity, frequency, duration, controllability, deterrents and reasons) and suicidal behaviour (preparatory acts, interrupted or aborted attempts, actual attempts and non-suicidal self-injurious behaviour)
Barbaresi WJ, et al. Mortality, ADHD, and psychosocial adversity in adults with childhood ADHD: a prospective study. Pediatrics 2013; 131: 637-644.
Giupponi G et al. The characteristics of mood polarity, temperament, and suicide risk in adult ADHD. Int J Environ Res Public Health 2020; 17(8): 2871.