Table 3.
Recent studies failing to confirm the relationship between MAOA-uVNTR, adversity, and at least one kind of antisocial outcome in humans
| Reference (year) | Sample | Gene(s) studied | Environmental variables | Outcome | Selected results |
|---|---|---|---|---|---|
| Prichard et al49 (2008) | 1,002 males | MAOA | General childhood adversity (including abuse) | Indicators of ASB | MAOA × adversity interaction only when comparing participants who suffered <2 adversity exposures with those who experienced 2–5 exposures. Carriers of the high activity allele showed the highest ASB scores. |
| Van der Vegt et al50 (2009) | 239 adopted boys | MAOA | Childhood maltreatment | Externalizing behavior (including aggressive and delinquent behavior) | The interaction between MAOA and maltreatment almost reached significance for delinquency, but not for aggression or the overarching externalizing scale. Main effect for MAOA in all measures, so that carriers of the high-activity allele obtained higher scores than MAOA-L participants. |
| Williams et al112 (2009) | 210 | MAOA | Early life stress | Electroencephalographic activity in a face-processing task | No interaction between number of early stressful events and genotype in any brain region. Interaction between genotype and sex in the processing of emotional-valenced faces. MAOA-L males had clearly reduced responses in several parietal, frontal, and occipital brain areas when presented with angry faces, whereas for females, genotype differences existed only in the superior occipital gyrus, and with an opposite pattern. |
| Verhoeven et al46 (2012) | 432 | MAOA | Childhood adversity | Anger, depression sensitivity | MAOA had a dose-dependent effect on the aggression reactivity facet of depression sensitivity in women, such that MAOA-H/H females scored higher than MAOA-H/L ones, who, in turn, had greater scores than MAOA-L/L. No genotype effects were found on trait or state anger. Childhood adversity did not interact with MAOA genotype for any antisocial outcome. |
| Haberstick et al48 (2014) | 4,316 males | MAOA | Childhood maltreatment | Adolescent conduct problems, adult antisocial behavior, convictions for violent crimes, disposition toward violence | Significant though mild main effect of MAOA gene on convictions for the whole sample, and on disposition toward violence in White males. Neither main nor interactive effects in any other score. The absence of G × E effects was not due to lack of statistical power. |
| Sadeh et al47 (2013) | 237 males | MAOA, 5HTTLPR | Childhood maltreatment | Psychopathy | Significant although small difference between MAOA-L and MAOA-H subjects in the impulsive– antisocial psychopathy dimension, higher for low-activity carriers. No interaction of the MAOA gene with childhood maltreatment. MAOA × 5HTTLPR interaction was not tested, but 5HTTLPR showed effects on the affective and interpersonal psychopathy dimensions. |
Notes: Studies included here were published in 2007 or later, when the last meta-analysis on the topic was published by Taylor and Kim-Cohen32 (2007), except if not listed in such article. Articles are presented chronologically; the order is alphabetical for papers published the same year. Samples include participants of both sexes unless otherwise specified.
Abbreviations: 5HTTLPR, serotonin transporter linked polymorphic region; ASB, antisocial behavior; G × E, gene–environment interaction; MAOA, monoamine oxidase A; MAOA-H, monoamine oxidase A high-activity allele; MAOA-L, monoamine oxidase A low-activity allele; uVNTR, upstream variable number of tandem repeats.