Brain structure and clinical profile point to neurodevelopmental factors involved in pedophilic disorder

Abstract

Objective: Pedophilic disorder (PD) is characterized bypersistent, intense sexual attraction to prepubertal children that the individual has acted on, or causes marked distress or interpersonal difficulty. Although prior research suggests that PD has neurodevelopmental underpinnings, the evidence remains sparse. To aid the understanding of etiology and treatment development, we quantified neurobiological and clinical correlates of PD.

Method: We compared 55 self-referred, help-seeking, non-forensic male patients with DSM-5 PD with 57 age-matched, healthy male controls (HC) on clinical, neuropsychological, and structural brain imaging measures (cortical thickness and surface area, subcortical and white matter volumes). Structural brain measures were related to markers for aberrant neurodevelopment including IQ, and the 2nd to 4th digit ratio (2D:4D).

Results: PD was associated with psychiatric disorder comorbidity and ADHD and autism spectrum disorder symptoms. PD patients had lower total IQ than HC. PD individuals exhibited cortical surface area abnormalities in regions belonging to the brain's default mode network and showed abnormal volume of white matter underlying those regions. PD subjects had smaller hippocampi and nuclei accumbens than HC. Findings were not related to history of child-related sexual offending. IQ correlated negatively with global expression of PD-related brain features and 2D:4D correlated with surface area in PD.

Conclusions: In the largest single-center study to date, we delineate psychiatric comorbidity, neurobiological and cognitive correlates of PD. Our morphometric findings, their associations with markers of aberrant neurodevelopment, and psychiatric comorbidities suggest that neurodevelopmental mechanisms are involved in PD. The findings may need consideration in future development of clinical management of PD patients.

Keywords: cerebral cortex; neurodevelopmental disorder; neuroimaging; pedophilic disorder; psychiatric comorbidity.

FIGURE 1

Brain abnormalities in PD (main analysis). Colored clusters represent areas in which significant differences in cortical surface area, thickness, and volume were found between PD and HC subjects. Data underwent Monte Carlo cluster‐wise corrections for multiple comparisons (see Figure S1 for uncorrected results). Statistical significance is displayed on a log(p)‐scale where positive values (warm colors) represent the PD < HC contrast. No negative values (cold colors) reflecting PD > HC patterns were observed. Cluster‐wise statistics are given in Table S1

FIGURE 2

2D:4D correlations. Correlations between 2D:4D ratios and cortical surface area, thickness, and volume in PD. Colored areas represent brain regions in which significant correlations were observed after multiple comparison correction (see Figure S3 for uncorrected results). Statistical significance is displayed on a ‐log(p) scale. Cold colors represent negative and warm colors positive correlations, respectively

FIGURE 3

2D:4D correlations and PD‐abnormality conjunction maps. Green areas indicate the regional overlap between areas where 2D:4D correlations (Figure 2) and PD‐related abnormalities were found (Figure 1)

FIGURE 4

Correlation between global morphometric PD abnormality expression score (LV‐score) and IQ. Relationships in this plot are quantified with Pearson correlation coefficients: r = −0.37 (p = 0.005) and r = −0.42 (p = 0.001) for PD and control groups, respectively