TABLE 3.

Summary of studies examining the relationship between cognitive inflexibility (CI) in children and adolescents with ASD and internalizing symptoms (n = 21)

Author (year); country	ASD diagnosis (criteria; measure)	N (male)	Age (years; M, SD); IQ (M, SD)	Cognitive flexibility (CF) measure	Internalizing (INT) symptom measure	Main findings	Quality score
Carter Leno et al. (2022); Canada	DSM‐IV‐TR; ADOS; ADI‐R	ASD: 242 (204) Typical shifting: 144 Atypical shifting: 98	Age: T1: 3.46 T5: 7.77 T6: 8.73 T7: 9.71 T8: 10.77 FSIQ (T6): Typical shifting: 86.55 (18.96) Atypical shifting: 82.70 (19.21)	BRIEF‐Shift (parent)	CBCL–internalizing (teacher)	Confounding variables controlled for: family income and autism symptom severity Cognitive Inflexibility and INT: Atypical Shifting vs. Typical Shifting: Greater CI significantly moderated the relationship between family‐stressful life events (F‐SLE) and future internalizing problems only in the group with atypical shifting abilities	0.79
Dieckhaus et al. (2021); USA	DSM‐5; ASD: ADOS‐2; ADHD: MINI‐Kid.	ASD: 35 (35) ADHD: 83 (63)	Age: ASD: 9.85 (0.88) ADHD: 9.56 (0.87) FSIQ: ASD: 101.63 (13.88) ADHD: 97.54 (15.02)	BRIEF‐Shift (Parent)	CBCL – Anxiety (Parent)	Confounding variables controlled for: gender and ethnoracial identity CI: 54% of ASD and 46% of ADHD group showed clinically elevated scores on Shift subscale (greater CI) INT: 51% of ASD and 36% of ADHD group showed clinically elevated anxiety problems on CBCL CI and INT: In both ASD and ADHD groups – greater CI associated with greater anxiety scores (ASD: Spearman's rho = 0.61, p < 0.001; ADHD: Spearman's rho = 0.60, p < 0.001)	0.82
Hollocks et al. (2022); UK	ICD‐10; ADOS‐2, ADI‐R	ASD: 81 (74)	Age: Wave 2: 15.4 (0.45) Wave 3: 23.2 (0.79) FSIQ (Wave 2): 83.5 (17.8)	WASI–Block Design Opposite Words Trail Making WCST (Performance‐based)	SDQ–emotional problems (parent–wave 2) BAI (parent–wave 3) BDI (parent–wave 3)	Confounding variables controlled for: verbal IQ, restricted and repetitive behaviors CI and INT (Age 16): CI significantly associated with increased emotional problems CI and INT (Age 23): greater CI at age 16 predicted greater anxiety and depression at age 23. CI partially mediated the relationship between anxiety, depression and emotional problems between age 16 and 23	0.83
* Ozsivadjian et al. (2021); UK	DSM‐5; DAWBA	ASD: 95 (71)	Age: 11 (3.2) FSIQ: (n = 59) 98.5 (2.3)	FS‐R (Parent)	RCADS ‐ Total (Parent) SDQ–emotional problems (parent)	Confounding variable controlled for: autism symptom severity CI and INT: CI positively associated with RCADS total (r = 0.39) and SDQ‐E (r = 0.34). CI did not significantly predict internalizing symptoms. CI significantly predicted higher intolerance of uncertainty (β =0.73, SE = 0.09; p ≤ 0.01)	0.91
Uljarevic et al. (2022); Australia	DSM‐5; ADI‐R; ADOS‐2.	PTEN‐ASD: 38 (30) Macro‐ASD: 25 (21) PTEN no ASD: 23 (15)	Age: PTEN‐ASD: 8.93 (4.75) Macro‐ASD: 11.99 (5.15) PTEN‐no ASD: 8.94 (4.85) FSIQ: PTEN‐ASD: 66.32 (13.71) Macro‐ASD: 74.30 (24.50) PTEN‐no ASD: 99.14 (17.40)	BRIEF–shift (parent)	CBCL 1.5–5/6–18–anxiety (parent)	Confounding variable controlled for: FSIQ CIs: Macro‐ASD group > PTEN‐no ASD group. CI and INT: Over the whole sample: there is a significant positive correlation between CI and anxiety (r = 0.53, p < 0.01).	0.86
*Crawley et al. (2020); UK	ADI‐R; ADOS.	ASD: 321 (232) NT: 251 (171)	Age: ASD: 16.67 (5.92) NT: 16.93 (6.02) FSIQ: ASD: 103.6 (15.28) NT: 108.95 (12.82)	Probabilistic reversal learning (PRL) (Performance‐based)	BAI (parent for children; self for adolescents); BYI‐II–anxiety (parent for children; self for adolescents)	Confounding variable controlled for: IQ, restricted and repetitive behavior CI: ASD < NT on task accuracy; ASD > NT on number of perseverative errors (greater CI) CI and INT: in ASD children, perseverative errors positively correlated with anxiety (r = 0.34)	1
* Sesso et al. (2020); Italy	DSM‐5; K‐SADS‐PL; ADI‐R; ADOS.	ADHD: 64 (56) ADHD + ASD: 19 (18) ADHD + ODD/CD: 43 (39) ADHD + ASD + ODD/CD: 25 (24)	Age: ADHD: 10.02 (2.49) ADHD + ASD: 9.58 (2.69) ADHD + ODD/CD: 9.37 (2.95) ADHD + ASD + ODD/CD: 8.4 (2.24) FSIQ: ADHD: 93 (14.98) ADHD + ASD: 92.69 (17) ADHD + ODD/CD: 96.86 (16.05) ADHD + ASD + ODD/CD: 98.94 (18.06)	BRIEF‐2 shift (parent)	CBCL 6–18‐internalizing problems (parent)	Confounding variable controlled for: none CI: no significant between‐group differences CI and INT: Items from the Shift (BRIEF) subscale and internalizing symptoms (CBCL) loaded onto the same principal component factor. For ASD group, there was a positive correlation between CI and internalizing problems ( r = 0 .51, p = 0.04)	0.91
Trimarco et al. (2020); Italy	DSM‐5; ADOS‐2	ASD: 21 (4) PKU: 15 (8) Control: 14 (6)	Age: ASD: 9.83 (1.95) PKU: 10.26 (2.26) NT: 10.20 (1.99) FSIQ: ASD: 94.33 (18.94) PKU: 95.47 (12.50)	NEPSY‐II: Switching, Response Set, Animal Sorting, Design Fluency (Performance‐based)	CBCL 6–18 internalizing problems (parent)	Confounding variable controlled for: none CI: ASD < NT group on design fluency and response set. No differences on switching tasks across PKU, ASD and NT groups INT: ASD > NT and PKU groups	0.73
Dajani et al. (2016); USA	ASD: ADOS‐G; ADOS‐2; ADI‐R; ADHD: DICA‐IV; CPRS‐R:L.	ASD: 24 (18) ADHD: 31 (22) NT: 44 (31)	Age: ASD: 10.30 (1.44) ADHD: 9.74 (1.24) NT: 10.47 (1.03) FSIQ: ASD: 102.48 (12.3) ADHD: 109.68 (12.64) NT: 119.66 (13.21)	BRIEF–shift (parent)	CBCL 6–18 internalizing problems (parent)	Confounding variable controlled for: head motion CI: weaker left SPL to right SPL connectivity is related to greater CI and worse emotional control in children	0.82
Berenguer et al. (2018); Spain	DSM‐5; ASD: SCQ; ADI‐R ADHD: SDQ	ASD: 30 (27) ADHD: 35 (32) ASD + ADHD: 22 (21) NT: 37 (23)	Age: ASD: 8.39 (1.3) ADHD: 9.14 (1.4) ASD + ADHD: 8.86 (1.3) NT: 8.54 (1.2) FSIQ: ASD: 100.37 (12.4) ADHD: 99.03 (9.8) ASD + ADHD: 102.86 (13.0) NT: 102.11 (8.9)	BRIEF–BRI (Teacher)	SDQ emotional problems (parents)	Confounding variables controlled for: sex, vocabulary and educational level of parents CI: ASD + ADHD > ASD, ADHD > NT INT: ASD, ADHD, ASD + ADHD > NT	0.86
*Gardiner et al. (2018); Canada	DSM‐IV‐TR; ADI‐R; ADOS.	ASD: 59 (51) NT: 67 (33)	Age: ASD: 10.07 (2.09) NT: 9.44 (1.73) FSIQ: ASD: 107.47 (13.25) NT: 111.37 (12.78)	BRIEF–shift (parent)	BASC‐2–internalizing behaviors (parent)	Confounding variable controlled for: IQ CI: ASD > NT INT: ASD > NT on depression symptoms CI and INT: No significant association between CI and anxiety; For the ASD group ‐ shift (β = 0.35, p = 0.02) and emotional control (β = 0.37, p = 0.03) scales emerged as unique significant contributors towards depression symptom severity. Greater CI also was associated with greater internalizing symptoms (r = 0.54)	0.91
* Vogan et al. (2018); Canada	ADOS/ ADOS‐2	ASD: 39 (34) NT: 34 (20)	Age: ASD: 10.6 (1.8) NT: 11.2 (2.1) FSIQ: ASD: 103.3 (14.7) NT: 115.4 (11.7)	BRIEF–BRI (parent)	CBCL–anxious/depressed (parent)	Confounding variable controlled for: age CI and INT: ASD group–Behavioral Regulation Index (BRI) from BRIEF showed significant correlation with anxiety/depression symptom severity ( r = 0.45 , p < 0.01) rated 2 years later. Regression analyses showed that more BRI problems at T1 predicted later symptoms of anxiety/depression (p < 0.01) at T2 (18% of variance)	0.82
*Lieb et al. (2017); USA	DSM‐IV‐TR	ASD: 127 (103)	Age: 13.95 (1.6)	BRIEF–shift (parent)	CBCL–depression (parent) YSR‐depression (self)	Confounding variables controlled for: age, gender, mode of participation CI and INT: CI positively associated with CBCL‐D ( r = 0.46 , p < 0.01) and YSR‐D (r = 0.34, p < 0.01)	0.86
Dajani et al. (2016); USA	ASD: ADOS‐G; ADOS‐2; ADI‐R; ADHD: DICA‐IV; CPRS‐R:L.	ASD: 30 (23) ADHD: 93 (72) ASD + ADHD: 66 (55) NT: 128 (98)	Age: ASD: 9.76 (1.36) ADHD: 9.79 (1.21) ASD + ADHD: 10.45 (1.40) NT: 10.03 (1.18) FSIQ: ASD: 106.10 (14.88) ADHD: 107.31 (11.67) ASD + ADHD: 99.99 (15.98) NT: 115.76 (12.23)	BRIEF (Parent) NEPSY‐II Statue subtest WISC‐IV Backward Digit Span (Performance‐based)	CBCL 6–18–Anxiety/Depression (Parent)	Confounding variable controlled for: diagnosis CI: ASD primarily in the “impaired” class for executive function (78%) (including 47% of children with ASD only, and 92% of children with both ASD and ADHD), with 20% in the “average” class. CI and INT: Socioemotional problems (i.e., including highest level of anxiety and depression) based on EF profile: “impaired” EF > “average” EF > “above average” EF	0.86
* Andersen et al. (2015); Norway	K‐SADS‐PL	ASD: 34 (28) NT: 45 (29)	Age: ASD: 11.6 (2.0) NT: 11.4 (1.5) FSIQ: ASD: 99.9 (17.4) NT: 104.5 (13.1)	CW4 (Performance‐based)	CBCL–Internalizing Problems (Parent)	Confounding variable controlled for: age CI: ASD > NT group, both showed similar rates of improvement over time. INT: ASD > NT on depression symptoms. ASD group showed improvement over time. CI and INT: Neither group showed any significant correlation between changes in flexibility and changes in depression. At baseline, greater internalizing symptoms was associated with greater CI ( r = 0.47 ).	0.77
Lawson et al. (2015); USA	DSM‐IV‐TR; ASD: ADI‐R; ADOS; ADHD: ADHD Rating Scale‐IV	ASD: 70 (63) ADHD: 55 (39)	Age: ASD: 10.07 (1.77) ADHD: 8.93 (2.69) FSIQ: ASD: 107.01 (19) ADHD: 111.53 (16.85)	BRIEF–Shift (Parent)	CBCL–Anxiety/Depression (Parent)	Confounding variables controlled for: age, gender CI: ASD > ADHD group. CI and INT: Across the whole sample, CI is positively associated with Anxious/Depressed (r = 0.39, p < 0.001) scale. Greater CI is also associated with higher anxious/depressed symptoms in the ASD group (B = 0.288, p < 0.001)	0.91
* Hollocks et al. (2014); UK	ICD‐10; ADI‐R; ADOS; SCQ.	ASD: 90 (82)	Age: 15.5. (0.47) FSIQ: 84.5 (17.2)	Card Sorting Task ‐ adapted from WCST (Performance‐based)	SDQ ‐ Emotional Symptoms (Parent)	Confounding variable controlled for: age CI and INT: Poorer card sorting task performance was associated with greater anxiety (r = −0.24 , p < 0.05) and greater depression (r = −0.23, p < 0.05)	0.91
Tachibana et al. (2013); Japan	DSM‐IV‐TR	ASD: 11 (8) [Intervention group: 6 (4); Control group: 5 (4)]	Age: ASD: 9.24 (0.82) [Intervention: 8.93 (0.71); Control: 9.62 (0.84)] FSIQ: ASD: 93.36 (13.20) [Intervention: 92.67 (15.66); Control: 94.20 (11.30)]	WCST (Performance‐based)	CBCL–Anxiety/Depression (Parent)	Confounding variable controlled for: none CI: intervention group showed significant improvement in number of “perseverative errors” and “categories achieved” on WCST compared to control group INT: Intervention group showed significant improvement on depression/anxiety symptom severity compared to controls	0.67
Teunisse et al. (2012); The Netherlands	DSM‐IV	ASD: 20 (20)	Age: 13.7 (1) FSIQ: 105.5 (13)	WCST‐S, CANTAB ID/ED (Performance‐based); BFRS‐R (Parent); BRIEF–shift (parent)	CBCL/4–18 total problems (parent)	Confounding variable controlled for: none CI: CANTAB ID/ED and WCST‐S are positively associated (r = 0.46, p < 0.05). Both parent‐based flexibility rating scales are positively associated with each other (r = 0.65, p < 0.01) CI and Total Problems: Both parent‐based flexibility scales (BFRS‐R, r = 0.51, p < 0.05; BRIEF Shift Score, r = 0.54, p < 0.05) significantly correlated with total problem score on CBCL. Neuropsychological tests did not significantly correlate with CBCL	0.64
* Yerys et al. (2009); USA	DSM‐IV; ADI/ADI‐R; ADOS; ADHD: Inattentive Type on the DSM‐IV ADHD parent rating scale	ASD: 28 (20) ASD + ADHD: 21 (18) NT: 21 (13)	Age: ASD: 9.7 (2.12) ASD + ADHD: 9.65 (1.62) NT:10.3 (1.76) FSIQ: ASD: 117.39 (18.68) ASD + ADHD: 111.24 (13.56) NT: 116.24 (11.53)	BRIEF‐Shift (Parent)	BASC–internalizing problems (parent)	Confounding variable controlled for: none CI: ASD + ADHD > ASD and NT, ASD group > NT INT: ASD and ASD + ADHD groups > NT group CI and INT: ASD and ASD + ADHD groups combined ‐ CI positively associated with internalizing symptoms (r = 0.46)	0.82
Happé et al. (2006); UK	DSM‐IV	ASD: 32 (32) ADHD: 30 (30) NT: 32 (32)	Age: ASD: 10.9 (2.4) ADHD: 11.6 (1.7) NT: 11.2 (2.0) FSIQ: ASD: 99.7 (18.7) ADHD: 99.1 (17.7) NT: 106.8 (13.4)	Verbal Fluency; Design Fluency; CANTAB ID/ED (Performance‐based)	SDQ Emotional Problems (Parent)	Confounding variables controlled for: age and FSIQ CI: ASD group: age positively associated with performance on Categories and Design fluency, and ID/ED CI and INT: Within the ADHD group, partialling out age revealed a significant correlation between Flexibility and SDQ Emotional symptoms (r = −0.56, p = 0.001). There were no associations between SDQ scores and flexibility in ASD or NT group	0.82

Note: *Indicates studies included in meta‐analysis. Statistics in italics and bold are correlations used for meta‐analysis.

Abbreviations: ADHD, Attention Deficit Hyperactivity Disorder; ADI‐(R), Autism Diagnostic Interview (Revised); ADOS, Autism Diagnostic Observation Schedule; APSD, Antisocial process Screening Device; ASD, Autism Spectrum Disorder; BASC, Behavior Assessment System for Children; BFRS‐R, Behavior Flexibility Rating Scale‐Revised; BRIEF‐(S), Behavior Rating Inventory of Executive Function (Shift subscale); CANTAB ID/ED, Cambridge Neuropsychological Test Automated Battery Intra/Extra dimensional set shift; CBCL, Child Behavior Checklist; CD, Conduct Disorder; CF, Cognitive Flexibility; CI, Cognitive inflexibility; CPRS, Conner's Parent Rating Scale; CU, Callous Unemotional; CW4, Color Word Interference task–condition 4; DAWBA, Development and Wellbeing Assessment; DICA, IV, Diagnostic Interview for Children and Adolescents IV; DSM, Diagnostic Statistical Manual; EXT, Externalizing; FS‐R, The Flexibility Scale‐Revised; FSIQ, Full Scale IQ; ICD, International Classification of Disease; K‐SADS‐PL, Kiddie Schedule for Affective Disorders and Schizophrenia for School‐Age Children–Present and Lifetime version; NEPSY‐II, A Developmental NEuroPSYchological assessment; NT, Neurotypical; ODD, Oppositional Defiant Disorder; PACS, Parental Account of Childhood Symptoms; PKU, Phenylketonuria; RBS‐R, Repetitive Behavior Scale–Revised; RCADS, Revised Child Anxiety and Depression Scale; SDQ, Strength and Difficulties Questionnaire; WCST, Wisconsin Card Sorting Task; WISC, Wechsler Intelligence Scale for Children.