The intermediate role of impulsive personality traits between attention‐deficit/hyperactivity disorder symptoms and suicidal ideation among patients with schizophrenia

Abstract

Aim

While there is a general consensus on Attention‐Deficit/Hyperactivity Disorder (ADHD) serving as a possible suicide risk factor in a broad range of populations, scant research has been dedicated to addressing ADHD and suicidality in schizophrenia. Therefore, there is a pressing need for studies that clarify these connections within the context of schizophrenia. This study was designed as one of the first to explore how impulsivity may serve as an indirect mediator of the impact of ADHD symptoms on suicidal ideation in patients with schizophrenia.

Methods

This study has a cross‐sectional design and was performed between January and June 2025 among Tunisian outpatients with clinically stabilized chronic schizophrenia.

Results

16.9% reported a lifetime personal history of suicidal attempt(s) and 11.3% a lifetime history of self‐harm. Impulsivity partially mediated the association between ADHD symptoms and suicidal ideation (indirect effect: Beta = 0.127; Boot SE = 0.033; Boot CI: 0.069; 0.196). Higher ADHD symptoms were significantly associated with greater impulsivity and directly associated with higher suicidal ideation. Additionally, higher impulsivity was significantly associated with higher suicidal ideation.

Conclusion

The present results stress the importance of paying more attention to the expression of impulsive personality traits in patients with schizophrenia who exhibit prominent ADHD symptoms and suicidal ideation.

Objective. To investigate whether impulsivity mediates the relationship between ADHD symptoms and suicidal ideation in individuals with schizophrenia. Conceptual Model. ADHD symptoms → Impulsivity → Suicidal ideation. Design & Participants. Cross‐sectional study (January–June 2025) among Tunisian outpatients with clinically stabilized chronic schizophrenia. Key Findings. 16.9% reported lifetime suicide attempts. 11.3% reported lifetime self‐harm. ADHD symptoms → ↑ Suicidal ideation (direct effect). ADHD symptoms → ↑ Impulsivity (Indirect path 1). Impulsivity → ↑ Suicidal ideation (Indirect path 2). Partial mediation confirmed (Indirect effect: β = 0.127; 95% CI [0.069–0.196]). Conclusion. Impulsivity plays a key mediating role linking ADHD symptoms to suicidal ideation in schizophrenia, highlighting the need to target impulsivity in risk assessment and intervention strategies.

INTRODUCTION

Attention‐deficit/hyperactivity disorder (ADHD) represents a typical neurodevelopmental disorder that involves the core symptoms of hyperactivity, inattention, and impulsive behaviors. ¹ ADHD diagnosis refers to a clinician‐confirmed disorder meeting clinical threshold criteria, with the diagnosis being based on a comprehensive clinical assessment, including a clinical interview. ADHD symptoms reflect a set of subclinical manifestations of ADHD that exist on a continuum with varying degrees of severity in both clinical and non‐clinical populations. The latter are measured using screening instruments to identify individuals who may be at risk for ADHD, but do not establish a clinical diagnosis. ² Therefore, ADHD symptoms appear to commonly occur in different mental health conditions, including psychotic disorders. ³ , ⁴ A large systematic review encompassing 36 studies and 30,726 individuals found a pooled lifetime prevalence of ADHD diagnosis of 18.49% in psychotic disorders, which is higher than in the general population, ⁵ calling for particular clinical and research attention to be paid to this comorbidity. Several theoretical explanations have been advanced to account for the co‐occurrence between ADHD and psychotic disorders, including shared environmental and neurodevelopmental influences (such as perinatal complications or polygenic risk). ⁶ , ⁷ , ⁸ Although the significant relationship between psychotic disorders and ADHD is well‐established, its potential implications in terms of clinical characteristics remain largely underexplored and represent a key research gap that further investigations should address. For example, while there is a general consensus on ADHD symptoms serving as a possible suicide risk factor in a broad range of populations, ⁹ very scant research has been dedicated to addressing ADHD symptoms and suicidality in schizophrenia. Therefore, there is a pressing need for studies that explore and clarify these connections within the context of schizophrenia.

The relationship between ADHD symptoms and suicidal ideation in schizophrenia

Schizophrenia is associated with a decreased life expectancy of up to 25 years ¹⁰ and greater premature mortality rates, ¹¹ with suicide being a frequent cause of death. ¹² The literature reports a prevalence of suicidal ideation, attempted suicide, and completed suicide in 34.5%, 20.3%, and 2.0% of people living with schizophrenia, respectively. ¹³ , ¹⁴ Although suicidality is highly prevalent, predicting and preventing suicide in people with schizophrenia remain challenging and often inaccurate, ¹⁵ with research in this area and population being relatively limited when contrasted with that conducted at the wider community level. A crucial, yet under‐researched, avenue for the prevention of suicide in schizophrenia lies in the role of ADHD symptoms. ADHD symptoms’ severity has been consistently and closely connected to suicidality in various populations, including adolescents ¹⁶ and non‐clinical young adults. ¹⁷ However, this relationship has to date received little research attention in schizophrenia. A study involving patients with various mental disorders found that high ADHD symptoms were significantly linked to increased risk of lifetime and past‐three‐month suicide attempts only in those with a mood disorder diagnosis. ¹⁸ However, it is worth noting that this study included a very small sample (n = 25) of patients with schizophrenia. ¹⁸ Gaining more knowledge on the nature and mechanisms linking ADHD symptoms to suicidal ideation in patients with schizophrenia is an important area for future research, given that it can help inform appropriate approaches to clinical risk assessment and the development of more effective suicide prevention strategies in individuals with schizophrenia. As a valuable addition to the existing small literature in this area, and to contribute to an enrichment of the theories of suicide in schizophrenia, this study proposes to focus attention on the relationship between ADHD symptoms and suicidal ideation in patients with schizophrenia, while taking into account impulsive personality traits as an underlying mediator.

Mediating effect of impulsive personality traits

Impulsivity is a multifaceted construct that can be defined as the tendency to act rapidly and prematurely, without foresight. ¹⁹ Impulsivity is a prominent feature of psychotic disorders and ADHD. Both disorders are neurobiologically connected to dysregulation of dopamine in the mesocortical and mesolimbic pathways. ²⁰ , ²¹ Therefore, theories have proposed that disrupted reward processing leads to trait‐based impulsivity in those with ADHD who develop psychosis. ³ , ²² , ²³ People with marked ADHD symptoms showed high levels of impulsive personality traits as assessed by self‐report measures ²⁴ and behavioral tasks. ²⁵ There is also solid evidence demonstrating that impulsive personality traits are involved in the development of suicidal ideation and behaviors. ²⁶ A significant relationship between impulsive personality traits and suicidality has specifically been reported in schizophrenia. ²⁷ Relative to individuals without schizophrenia, those with schizophrenia who have attempted suicide are characterized as impulsive, as reflected in using more violent suicidal methods (especially jumping) ²⁸ and have a higher lethality of index suicide attempt. ²⁹ , ³⁰ Hence, ADHD symptoms may have an effect on suicidal ideation through impulsive personality traits in those diagnosed with schizophrenia.

Rationale and objectives

Investigating the potential connections linking ADHD symptoms, impulsive personality traits, and suicidal ideation in patients with schizophrenia is particularly relevant in Tunisia. A previous Tunisian naturalistic study found that a high proportion (38.7%) of patients exhibit high levels of impulsive personality traits since the very early stages of the disease, which did not decrease over a 12‐month follow‐up period, ³¹ suggesting that the current intervention approach was not effective in addressing this problem. In addition, ADHD symptoms ³² and self‐reported impulsive personality traits ³³ may both be subject to cross‐cultural variations. Studies performed in Tunisia documented a concerning prevalence of suicidal ideation and behavior in people with early psychosis and during follow‐up. ³⁴ However, we could not find any previous studies evaluating ADHD symptoms in patients with psychotic disorders in Tunisia. Following these considerations, this study was designed as one of the first to explore how impulsive personality traits may serve as an indirect mediator of the impact of self‐reported ADHD symptoms on suicidal ideation in patients with schizophrenia from Tunisia. Based on prior literature, it is hypothesized that a higher degree of self‐rated ADHD symptoms would be directly and indirectly associated with greater severity of suicidal ideation through higher levels of impulsive personality traits.

METHODS

Sample and study design

This study has a cross‐sectional design and was performed between January and June 2025 among individuals with chronic schizophrenia. The target population consisted of outpatients who were attending our department of psychiatry during this period for their follow‐up visit after hospital discharge. In order to be enrolled in this study, patients should have met the following criteria: (1) be aged 18 years and over, (2) meet the diagnostic criteria for schizophrenia of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM‐5‐TR) ¹ , (3) be clinically stabilized and not in an acute episode of the illness, and (4) be treated with a stable dose of the same antipsychotic(s) for at least three months. Patients who had comorbid intellectual disability or ADHD disorder according to the DSM‐5‐TR criteria, based on a clinical interview, were excluded. Each patient was informed that they can withdraw at any time without prejudice to their care, while also ensuring the confidentiality of their personal information. After voluntarily giving their informed consent, those fulfilling eligibility criteria were invited to complete a paper‐and‐pencil survey involving both interviewer‐administered and self‐report instruments. Patients were assisted if they were not able to fill in the questionnaires themselves. All procedures were conducted in accordance with the STROBE (i.e. Strengthening the Reporting of Observational Studies in Epidemiology) guidelines, ³⁵ and were granted ethical approval by the Ethics Committee of Razi Hospital, Manouba, Tunisia.

Sample size calculation

The minimum required sample size was estimated using the formula proposed by Fritz and MacKinnon for mediation analysis, considering a small‐to‐medium effect size (f = 0.26), an alpha error of 0.05, a statistical power of 80%, and 11 variables to be entered in the model (L = 7.85). ³⁶ Based on these parameters, a minimum of 128 participants was deemed necessary to achieve sufficient statistical power.

Measuring instruments

Socio‐demographic and clinical data

The questionnaire used to collect data started with questions regarding age, sex, level of education, marital status, and substance use. A section of the questionnaire collected information about clinical characteristics such as number of hospitalizations, duration of illness, personal and family history of suicide attempts, personal history of self‐harm, type of antipsychotic medication taken (First‐generation vs. second‐generation), and route of administration of antipsychotic(s) (Long‐acting injectable vs. oral). Of note, only first‐generation antipsychotics are available in long‐acting injectable form in Tunisia.

The Adult ADHD Self‐Report Scale Version 1.1 6‐Question Screener (ASRS‐6)

This self‐report measure represents a subset of the WHO's 18‐question Adult ADHD Self‐Report Scale v1.1, which was developed based on DSM‐IV criteria. ³⁷ The ASRS‐6 evaluates the frequency of occurrence of a range of ADHD symptoms over the last 6 months through a five‐point scale that ranges from 0 (never) to 4 (very often). The ASRS‐6 encompasses six items measuring two domains: four items measure “Inattention” (e.g., How often do you have problems remembering appointments or obligations?) and two items measure “Hyperactivity‐Impulsivity” (e.g., How often do you fidget or squirm with your hands or feet when you have to sit down for a long time?). Total scores vary between 0 and 24, with higher scores indicating greater ADHD symptoms. The 6‐question screener has been translated into a number of languages, including Arabic, ³⁸ using the standard WHO translation and back‐translation protocol. ³⁹ The Arabic translated version used in this study is available on the official website (https://www.hcp.med.harvard.edu/ncs/asrs.php).

The Columbia‐Suicide Severity Rating Scale (C‐SSRS)

The C‐SSRS is a semi‐structured interview that evaluates the severity of suicidal ideation via five items. ⁴⁰ The total score varies between 0 and 5, with higher scores indicating greater severity of suicidal ideation, whereas a score of “0” reflects no suicidality. The Arabic validated version was used, ⁴¹ , ⁴² which showed a Cronbach's alpha value of 0.83 in the present sample.

The impulsive behavior short scale–8 (I‐8)

The I‐8 is a self‐completed instrument assessing four different impulsive personality facets through 8 items (two items each): urgency, lack of premeditation, sensation seeking, and lack of perseverance. ⁴³ Items can be scored on a six‐point Likert‐type scale, ranging from 0 (does not apply at all) to 5 (applies completely). Greater scores reflect higher levels of impulsive personality traits. The Arabic version of the I‐8 was used in this study, ⁴⁴ which yielded a Cronbach's α value of 0.73 in our sample.

Statistical analysis

The SPSS v.27 software was used for the statistical analysis. The suicidal ideation score was normally distributed, as shown by its skewness and kurtosis values between ±1. The Student t test was used to compare a continuous variable and a dichotomous variable, the ANOVA test to compare three or more means, and Pearson's test to correlate two continuous variables. The mediation analysis was performed using PROCESS MACRO (a SPSS add‐on) v.4.2 Model 4. Four pathways were computed: Pathway A from ADHD symptoms to impulsive personality traits, Pathway B from impulsive personality traits to Suicidal Ideation, and Pathways C and C’ reflecting the total and direct association of ADHD symptoms on Suicidal Ideation, respectively. Covariates entered into the model were those that showed p < 0.002 after Bonferroni correction (calculated by dividing 0.05 by the total number of variables = 33) in the bivariate analysis. P < 0.05 was considered statistically significant in the mediation model.

RESULTS

In total, 302 patients (33.4% females) completed the questionnaire. The full description of the sample is in Table 1. Among participants, 12.6% had a family history of suicidal attempts, 16.9% reported a lifetime personal history of suicidal attempt(s), and 11.3% a lifetime history of self‐harm.

Table 1.

Sociodemographic and other characteristics of the sample (N = 302).

Variable	N (%)
Sex
Male	201 (66.6%)
Female	101 (33.4%)
Profession
Unemployed	218 (72.2%)
Employed	84 (27.8%)
Marital status
Married	67 (22.2%)
Unmarried (Single, divorced, or widowed)	235 (77.8%)
Education level
High‐school level or less	203 (67.2%)
University level	99 (32.8%)
Monthly outcome
<500 DT	200 (66.2%)
500‐1500 DT	94 (31.1%)
1500‐2000 DT	8 (2.6%)
Living environment
Rural	94 (31.1%)
Urban	208 (68.9%)
Living arrangement
Alone	51 (16.9%)
With parents/partner	236 (78.1%)
With friends	15 (5.0%)
Tobacco use
No	130 (43.0%)
Yes	172 (57.0%)
Lifetime cannabis use
No	206 (68.2%)
Yes	96 (31.8%)
Alcohol consumption
Never	193 (63.9%)
Occasionally	82 (27.2%)
Weekly	20 (6.6%)
Daily	7 (2.3%)
Other drugs
No	244 (80.8%)
Yes	58 (19.2%)
First‐generation antipsychotic
No	138 (45.7%)
Yes	164 (54.3%)
Second‐generation antipsychotic
No	117 (38.7%)
Yes	185 (61.3%)
Route of administration of antipsychotic(s)
Long‐acting injectable	78 (25.8%)
Oral	224 (74.2%)
Number of antipsychotic(s) taken
1	228 (75.5%)
2	70 (23.2%)
3	4 (1.3%)
Benzodiazepines
No	233 (77.2%)
Yes	69 (22.8%)
Mood stabilizers
No	239 (79.1%)
Yes	63 (20.9%)
Antidepressants
No	266 (88.1%)
Yes	36 (11.9%)
Anticholinergics
No	162 (53.6%)
Yes	140 (46.4%)

	Mean ± SD
Age (years)	32.57 ± 7.12
Duration of untreated psychosis	1.97 ± 2.15
Number of hospitalizations	2.85 ± 3.44
Age at the onset of the disease	22.24 ± 4.72
ADHD symptoms	6.21 ± 4.32
impulsive personality traits	21.71 ± 6.55

Bivariate analysis of factors associated with suicidal ideation score

Bivariate analyses were conducted solely as exploratory screening procedures to identify potential confounding variables for inclusion in the mediation model and should not be interpreted as independent or confirmatory findings. A higher mean suicidal ideation score was found in participants living with friends vs the other categories (Table 2). Furthermore, greater levels of impulsive personality traits and ADHD symptoms were associated with higher suicidal ideation (Table 3).

Table 2.

Bivariate analysis of factors associated with suicidal ideation score.

Variable	Mean ± SD	t	df	P	Effect size
Gender		2.10	300	0.037	0.256
Male	4.87 ± 5.47
Female	6.26 ± 5.40
Profession		1.90	300	0.058	0.244
Unemployed	5.70 ± 5.55
Employed	4.37 ± 5.19
Civil status		0.68	300	0.499	0.094
Married	5.73 ± 5.47
Unmarried (Single, divorced, or widowed)	5.22 ± 5.48
Education level		1.41	213.93	0.159	0.167
High‐school level or less	5.63 ± 5.65
University level	4.72 ± 5.08
Monthly outcome		1.08	2.30	0.341	0.007
<500 DT	5.29 ± 5.63
500–1500 DT	5.19 ± 5.22
1500–2000 DT	8.13 ± 4.12
Living environment		2.54	300	0.012	0.316
Rural	6.51 ± 5.43
Urban	4.80 ± 5.42
Living arrangement		8.46	2.30	<0.001	0.054
Alone	7.41 ± 6.03
With parents/partner	4.67 ± 5.24
With friends	8.60 ± 6.03
Family history of suicidal attempts		2.08	300	0.038	0.362
No	5.08 ± 5.43
Yes	7.05 ± 5.57
Personal history of suicidal attempts		2.93	300	0.004	0.450
No	4.92 ± 5.32
Yes	7.35 ± 5.85
Personal history of self‐harm		1.76	300	0.079	0.320
No	5.13 ± 5.35
Yes	6.88 ± 6.29
Tobacco use		0.11	300	0.915	0.012
No	5.29 ± 5.10
Yes	5.36 ± 5.76
Lifetime cannabis use		0.36	300	0.722	0.044
No	5.41 ± 5.46
Yes	5.17 ± 5.53
Alcohol consumption		0.34	3.30	0.800	0.003
Never	5.33 ± 5.38
Occasionally	5.07 ± 5.32
Weekly	5.85 ± 6.56
Daily	7.00 ± 7.28
Other drugs use		0.74	300	0.459	0.108
No	5.22 ± 5.39
Yes	5.81 ± 5.86
First‐generation antipsychotic(s)		2.04	3300	0.042	0.236
No	6.03 ± 5.79
Yes	4.74 ± 5.14
Second‐generation antipsychotic(s)		2.39	300	0.018	0.282
No	4.39 ± 5.22
Yes	5.92 ± 5.56
Route of administration of antipsychotic(s)		2.94	300	0.004	0.386
Long‐acting injectable	3.78 ± 5.29
Oral	5.87 ± 5.45
Number of AP		0.09	2.30	0.912	0.001
1	5.41 ± 5.62
2	5.09 ± 5.15
3	5.25 ± 2.99
Benzodiazepines		0.05	300	0.963	0.006
No	5.34 ± 5.52
Yes	5.30 ± 5.37
Mood stabilizers		0.96	300	0.338	0.136
No	5.18 ± 5.43
Yes	5.92 ± 5.67
Antidepressants		0.85	300	0.399	0.150
No	5.23 ± 5.53
Yes	6.06 ± 5.08
Anticholinergics		1.83	300	0.069	0.211
No	5.86 ± 5.54
Yes	4.71 ± 5.35

Note: Bold numbers indicate a significant p value after Bonferroni correction (p ≤ 0.002).

Table 3.

Pearson correlation matrix.

	1	2	3	4	5	6
1. Suicidal ideation	1
2. Impulsive personality traits	0.43***	1
3. Age	0.04	−0.07	1
4. Duration of untreated psychosis	−0.004	−0.05	0.19***	1
5. Age at onset of the disease	0.03	0.02	0.58***	−0.01	1
6. Number of hospitalizations	−0.17**	−0.24***	0.17**	0.01*	−0.06	1
7. ADHD symptoms	0.29***	0.29***	−0.01	0.04	0.01	−0.08

^** p < 0.01;

^*** p < 0.001.

Analysis of mediation

Prior to conducting the mediation analysis, the assumptions of linear regression were examined. Visual inspection of scatterplots indicated linear relationships between variables and no evidence of heteroscedasticity. The normality of residuals was assessed using histograms and normal P‐P plots, which showed an approximately normal distribution with minor deviations, considered acceptable given the sample size (n = 300). No problematic multicollinearity was observed according to the variance inflation factor (VIF) and tolerance values. The mediation analysis taking the suicidal ideation score as the dependent variable was adjusted over patients’ living arrangement. Impulsive personality traits partially mediated the association between ADHD symptoms and suicidal ideation (indirect effect: Beta = 0.127; Boot SE = 0.033; Boot CI: 0.069; 0.196). Higher ADHD symptoms were significantly associated with greater impulsive personality traits and directly associated with higher suicidal ideation. Additionally, higher impulsive personality traits were significantly associated with higher suicidal ideation (Figure 1).

Figure 1.

Mediation model taking impulsive personality traits as a mediator between ADHD symptoms and suicidal ideation. (a) Relation between ADHD symptoms and impulsive personality traits (R ² = 0.108); (b) Relation between impulsive personality traits and suicidal ideation (R ² = 0.246); (c) Total effect of ADHD symptoms on suicidal ideation (R ² = 0.133); (c’) Direct effect of ADHD symptoms on suicidal ideation. The numbers represent regression coefficients and their standard errors. ***p < 0.001.

DISCUSSION

Understanding the potential correlates of suicidality in patients with schizophrenia is critical, as these may serve as warning signs and offer unique opportunities to prevent premature loss of life in this vulnerable population. In this paper, particular attention is given to the intricate association between ADHD symptoms and suicidal ideation in schizophrenia. Our results showed that impulsive personality traits acted as a partial mediator in this association. Those who exhibited marked ADHD symptoms were more likely to have higher levels of impulse control difficulties, and their impulsive personality traits were, in turn, related to more suicidal ideation in our patients with schizophrenia. These results may have significant clinical implications for suicide prevention efforts in this highly vulnerable population.

In this study, ADHD symptoms had a significant direct effect on suicidal ideation. This is consistent with earlier research showing that individuals diagnosed with schizophrenia can possess traits characters of ADHD, ⁵ and that these do not seem to be insignificant for their mental health, as they might have a role in increasing the risk of suicide‐related outcomes in this population. Although it has been largely admitted that ADHD is a strong risk factor for suicidality in all age groups and both sexes, ⁹ this link has not been explicitly explored and elucidated among patients with schizophrenia in previous literature. We could find only a single study that examined the association between ADHD symptoms and suicide attempts in a mixed sample of patients with various mental disorders, in which no significance was reported in the schizophrenia group. ¹⁸ However, the sample size was too small compared to ours and may not have provided sufficient power to detect some effects.

In line with prior theories and research findings, mediation analysis showed that subthreshold ADHD symptoms exerted an indirect effect on suicidal ideation through the intermediate role of impulsive personality traits, thus supporting our study hypothesis. More specifically, patients with both increased severity of ADHD symptoms and greater impulsive personality traits based on self‐report were more likely to experience suicidal ideation. This significant indirect pathway mirrors that seen in general population studies, which consistently observed that ADHD symptoms are an independent risk factor for suicidal thoughts and behaviors, ¹⁷ and that the effect of ADHD symptoms on suicidal ideation can be explained by the UPPS‐P model of impulsive personality traits, which relates sensation seeking, lack of perseverance, lack of premeditation, positive urgency, and negative urgency to suicidality. ⁴⁵ These findings might suggest that, as in other populations, ⁴⁶ , ⁴⁷ the suicidal drive in schizophrenia could be attributed to ADHD manifestations and related impulsive personality traits. In other terms, it can be suggested that impulsive personality traits may not by themselves exacerbate the severity of suicidal ideation in patients with schizophrenia, but that when coupled with adult ADHD symptoms are more likely to correlate with increased likelihood of suicidality. That is, patients with greater levels of ADHD symptoms might not inhibit their impulses as effectively as those with less ADHD symptoms, and are subsequently more likely to report higher levels of suicidal ideation.

Clinical implications and directions for future research

The study findings showed that, in addition to the direct effect of ADHD symptoms, these can also affect suicidal ideation through the indirect role of impulsive personality traits. Thus, schizophrenia patients with prominent ADHD symptoms seem to be more likely to exhibit suicidal thoughts through the mediating effect of increased impulsive personality traits. In light of these findings, our study generates new information to help guide suicide risk assessment in people diagnosed with schizophrenia, underscoring the necessity to consider a range of influencing factors when evaluating suicidality in patients with schizophrenia. Particularly, the present results stress the importance of paying more attention to the expression of impulsive personality traits in those who exhibit prominent ADHD symptoms and suicidal ideation. Because this is an important yet largely understudied area, further research still needs to explore the relationship between ADHD symptoms and suicidality in depth by deciphering its underlying processes in the schizophrenia population. Such a line of research could be helpful for developing personalized strategies to prevent the occurrence of suicidal ideation in this already vulnerable group.

Study limitations

Our study has a few limitations to be acknowledged. First, inference of causality cannot be supported because of the cross‐sectional design. Additional experimental or longitudinal studies are crucial to establish causal mediation paths and better capture the dynamic changes between ADHD symptoms, impulsive personality traits, and suicidal ideation over time. Second, suicide‐related stigma, which is still very prevalent in our context, ⁴⁸ may have affected the likelihood of reporting suicidal thoughts by patients. Third, participants were recruited from a single site and hospital, which may have impacted the generalizability of our results. Information bias is plausible because of possible over‐ or under‐estimation of the questions. Future studies should be conducted in diverse cultural contexts and broader regions for more representativeness and wider applicability of our conclusions. Another limitation is that impulsivity as an ADHD symptom domain may overlap conceptually with impulsivity as a personality trait, but they still represent distinct constructs. In ADHD, impulsivity is one of the core diagnostic domains (alongside hyperactivity and inattention). It refers to behavioral disinhibition (i.e. inhibitory control deficits) that is often evident early in development and tied to neurodevelopmental dysfunction. Its stability is tied to the disorder trajectory. As a personality trait, impulsivity refers to a stable personality tendency that varies across individuals in the general population. It is multifaceted (involving emotional, cognitive, and motivational aspects) and can be adaptive or maladaptive. Therefore, individuals with high levels of ADHD symptoms often score high on trait impulsivity; however, not all individuals with high levels of trait impulsivity facets have ADHD symptoms. Previous research has shown that impulsivity measures (assessing underlying impulsivity traits: Urgency, lack of Premeditation, lack of Perseverance, and Sensation Seeking) are relevant to ADHD subtype classification and trajectories of psychopathology. ⁴⁹ Therefore, the assessment of impulsivity traits was encouraged by researchers, as it has been considered a key to the understanding of individuals’ behavioral outcomes and to informing treatment interventions. ⁴⁹ Finally, although this study gathered some information about current antipsychotic medication characteristics, it did not collect data on dose, duration, adherence, and recent medication changes. To address this limitation, future research should consider these factors to help draw clearer conclusions.

CONCLUSION

This study provides empirical support to the theoretical background involving impulsive personality traits as a key mechanism behind the association between ADHD features and suicidality. The novelty of this study lies in the investigation of these pathways in patients with schizophrenia, which has promising implications for suicide prevention in this at‐risk group. Findings helped to identify ADHD symptoms and impulsive personality traits as factors that can be targeted to prevent suicide, and intervene early and effectively to enhance patient safety when suicidal ideation arises. Future studies are warranted to replicate and confirm our findings using prospective data.

AUTHOR CONTRIBUTIONS

F.F.R. designed the study. A.B. and J.Z. processed the data. F.F.R. and S.H. drafted the manuscript. S.H. carried out the analysis and interpreted the results. F.G. and M.C. reviewed the paper for intellectual content. All authors reviewed the final manuscript and gave their consent.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest.

ETHICS APPROVAL STATEMENT

Each participant provided a voluntary oral informed consent to participate before beginning the survey. The research protocol was approved by the ethics committee of the Razi psychiatric hospital, Manouba, Tunisia. The study was performed following the standards for medical research involving human subjects recommended by the Declaration of Helsinki for human research.

PATIENT CONSENT STATEMENT

N/A.

CLINICAL TRIAL REGISTRATION

N/A.

DATA AVAILABILITY STATEMENT

The datasets generated and/or analyzed during the current study are not publicly available due to restrictions from the ethics committee, but are available from the corresponding author on reasonable request.