Digit ratio (2D:4D), impulsiveness and aggression in male heroin addicts: A prospective controlled study

Çiçek, İsmet Esra; Çiçek, Erdinç; Demirel, Başak; Ayhan, Medine Gıynaş; Varsak, Nalan; Özbek, Seda Yıldırım; Selçuk, Mahmut; Eren, İbrahim

doi:10.1016/j.paid.2017.05.031

Cited by 14 publications

(7 citation statements)

References 48 publications

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“…The literature search (Fig. 1 ) identified 19 partly dependent articles (Vehmas et al 2006 ; Kornhuber et al 2011 , 2013 ; Manning and Fink 2011 ; Herschl et al 2012 ; Borkowska and Pawlowski 2013 ; Romero-Martínez et al 2013 ; Park et al 2014 ; Hoskin and Ellis 2015 ; Han et al 2016 ; Canan et al 2017 , 2018 ; Lenz et al 2017 , 2018a ; Müller et al 2017 ; Cicek et al 2017 ; Hoskin 2017 ; Hobson 2018 ; Kim et al 2018 ) and 18 independent samples. Two studies (Hoskin and Ellis 2015 ; Hoskin 2017 ) are based on the same collective and, therefore, count as one independent sample in our analysis.…”

Section: Resultsmentioning

confidence: 99%

Digit ratio (2D:4D) in relation to substance and computer use: a meta-analysis

et al. 2019

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Human studies have reported inconsistent associations between the length ratio of the second finger to the fourth finger (2D:4D), which is a proxy for prenatal androgen load, and substance or computer use in adolescents and adults. This metaanalysis quantifies the magnitude of this relationship and investigates the roles of sex, definition of caseness, different forms of addiction, the hand measured (right hand versus left hand), and other cohort characteristics. Univariate random-effects meta-analyses were performed, and moderators were tested with Bonferroni-corrected meta-regression analyses. The study included 18 independent samples with a total of 175,955 participants (96,316 males and 79,639 females). There was a significant difference in 2D:4D between the substance and computer-using subjects and the controls for the combined sample (Hedge's g = − 0.178 [− 0.291; − 0.064]) and for males (Hedge's g = − 0.260 [− 0.399; − 0.122]), but not for females. These effects were amplified when only analyzing studies that compared dependent versus non-dependent subjects (combined sample: g = − 0.325 [− 0.492; − 0.157]; males: g = − 0.427 [− 0.564; − 0.291]), but did not reach significance in the subgroup of studies examining other parameters of substance and computer use. When analyzing different forms of substance and computer use separately, alcohol intake and computer use revealed a significant difference in the standardized mean. Again, the effects were amplified when analyzing the subgroup of males and the subgroup of studies comparing dependent versus non-dependent subjects, with effect sizes showing Hedge's g values as many as − 0.552 [− 0.785; − 0.319] (alcohol-dependent males). Thus, this meta-analysis confirms that lower 2D:4D is associated with substance and computer dependency. Further studies are encouraged to explore the link between intrauterine hormone environment and addiction risk.

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Section: Resultsmentioning

confidence: 99%

Digit ratio (2D:4D) in relation to substance and computer use: a meta-analysis

et al. 2019

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“…Two papers recruited individuals with alcohol dependence and were conducted in South Korea [ 59 ] and Germany [ 60 ]. Moreover, we included three studies involving participants with heroin dependence, which were conducted in Turkey [ 61 , 62 ] and Germany [ 63 ]. Participants were all adults, with mean ages ranging from 22.8 [ 61 ] to 51.2 [ 59 ].…”

Section: Resultsmentioning

confidence: 99%

“…Participants were all adults, with mean ages ranging from 22.8 [ 61 ] to 51.2 [ 59 ]. Three studies included only men [ 59 , 61 , 62 ], while in the remaining two articles samples were mixed. Three papers measured 2D:4D ratio in both hands; one paper considered the average between the left and right hand [ 60 ] and one measured only right hand [ 62 ].…”

Section: Resultsmentioning

confidence: 99%

“…Three studies included only men [ 59 , 61 , 62 ], while in the remaining two articles samples were mixed. Three papers measured 2D:4D ratio in both hands; one paper considered the average between the left and right hand [ 60 ] and one measured only right hand [ 62 ]. Measure-ments were indirect in three papers [ 59 , 60 , 63 ], and direct in two articles [ 61 , 62 ].…”

Section: Resultsmentioning

confidence: 99%

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Second-to-Fourth Digit Ratio (2D:4D) in Psychiatric Disorders: A Systematic Review of Case-control Studies

Fusar-Poli

Rodolico

Sturiale

et al. 2021

Clin Psychopharmacol Neurosci

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The second-to-fourth digit ratio (2D:4D) is an indirect, retrospective, non-invasive measure that correlates negatively with intrauterine exposure to testosterone. The present meta-analysis aimed to evaluate if 2D:4D differs between patients with psychiatric disorders and controls. In September 2019, we searched in Web of Knowledge, PsycINFO, Embase, and CINHAL, and retrieved 619 papers. We finally included 43 case-control studies which compared the 2D:4D ratio of patients with autism spectrum disorder (ASD) (n = 16), schizophrenia (n = 8), gender non-conformity (n = 7), addictions (n = 5), attention deficit-hyperactivity disorder (ADHD) (n = 4), mood disorders (n = 2), and intellectual disability (n = 1) to non-clinical controls. Meta-analyses showed that, overall, psychiatric patients had lower 2D:4D than healthy controls (n = 43, overall sample = 9,484, mean difference = −0.0056, 95% confidence interval from −0.0093 to −0.002, I 2 = 74%), with more pronounced differences in the right hand, males, and children. Considering psychiatric disorders individually, significant differences were found in the ASD, ADHD, and addictions groups, in which 2D:4D was significantly lower than healthy controls. Conversely, the right hand of males with schizophrenia showed higher 2D:4D than healthy controls. No other significant differences were detected. Although our results need to be cautiously interpreted and find limited applications in clinical practice, they may suggest that 2D:4D is altered in some psychopathological conditions, underlining the role of prenatal exposure to sex steroids in the etiology of psychiatric disorders.

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“…Similar to the results of our study, several studies did not detect any relation between 2D:4D ratios and aggression. [34][35][36] On the other hand, studies are reporting an association between low 2D:4D ratios and increased aggression. [37][38][39][40] Systematic reviews and meta-analyses have been less equivocal in that, depending on the outcome under investigation (e.g., general aggression, sensation seeking/impulsivity), the effects of the 2D:4D ratios tend to be rather weak in overall magnitude.…”

Section: Discussionmentioning

confidence: 99%

The Relationship between Second-to-Fourth Digit Ratios, Attention-Deficit/Hyperactivity Disorder Symptoms, Aggression, and Intelligence Levels in Boys with Attention-Deficit/Hyperactivity Disorder

Işık

Kılıç

Aktepe

et al. 2020

Psychiatry Investig

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Objective Observations of sex differences have led some scientists to doubt whether the neuroendocrine system is involved in attentiondeficit/hyperactivity disorder (ADHD) etiology. One of the interesting study subjects in this context is prenatal steroid hormone exposure. The aim of the present study was to replicate and extend previous work by addressing two research questions: 1) Are second-tofourth digit (2D:4D) ratios lower in ADHD than in controls? 2) Is there a correlation between 2D:4D ratios and symptoms of ADHD, aggression and intelligence scores in boys with ADHD?Methods The study included 100 treatment-naive male children diagnosed with ADHD and 55 healthy male children. We measured the ratios of 2D:4D and administered a Wechsler Intelligence Scale for Children-Revised to assess IQ scores, as well as behavioral rating scales, in children with ADHD and comparison individuals.Results We observed lower 2D:4D ratios in the right hand in ADHD in comparison to the control group. The left-hand ratios of 2D:4D, however, did not differ between ADHD and control groups. There were negative correlations between the left-hand 2D:4D ratios and the hyperactivity scores. However, no significant correlation was detected between right-hand 2D:4D ratios and the psychological questionnaire scores.Conclusion These results provide further evidence that fetal androgen exposure may contribute to the pathophysiology of ADHD, at least in boys.

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Digit ratio (2D:4D), impulsiveness and aggression in male heroin addicts: A prospective controlled study

Cited by 14 publications

References 48 publications

Digit ratio (2D:4D) in relation to substance and computer use: a meta-analysis

Digit ratio (2D:4D) in relation to substance and computer use: a meta-analysis

Second-to-Fourth Digit Ratio (2D:4D) in Psychiatric Disorders: A Systematic Review of Case-control Studies

The Relationship between Second-to-Fourth Digit Ratios, Attention-Deficit/Hyperactivity Disorder Symptoms, Aggression, and Intelligence Levels in Boys with Attention-Deficit/Hyperactivity Disorder

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