Progress in Neurobiology 122 (2014) 1–23 Contents lists available at ScienceDirect Progress in Neurobiology jo urnal homepage: www.elsevier.com/locate/pneurobio Brain alterations in paedophilia: A critical review a, a b Sebastian Mohnke *, Sabine Mu¨ ller , Till Amelung , c d e Tillmann H.C. Kru¨ ger , Jorge Ponseti , Boris Schiffer , f b a, Martin Walter , Klaus M. Beier , Henrik Walter ** a Charite´ – Universita¨tsmedizin Berlin, Department of Psychiatry and Psychotherapy, Charite´platz 1, 10117 Berlin, Germany b Charite´ – Universita¨tsmedizin Berlin, Institute of Sexology and Sexual Medicine, Luisenstr. 57, 10117 Berlin, Germany c Hannover Medical School, Department of Clinical Psychiatry, Social Psychiatry, and Psychotherapy, Carl-Neuberg-Str. 1, 30625 Hannover, Germany d University Medical Center Schleswig-Holstein, Section for Sexual Medicine, Arnold-Heller-Str. 3, 24105 Kiel, Germany e Division of Forensic Psychiatry, Department of Psychiatry, Psychotherapy and Preventive Medicine, LWL-University Hospital, Bochum, Germany f Otto-von-Guericke-University Magdeburg, Department of Psychiatry, Leipziger Str. 44, 39120 Magdeburg, Germany A R T I C L E I N F O A B S T R A C T Article history: Psychosocial and biological factors have been implicated in paedophilia, such as alterations in brain Received 5 December 2013 structure and function. The purpose of this paper is to review the expanding body of literature on this Received in revised form 25 July 2014 topic including brain abnormality case reports, as well as structural and functional neuroimaging Accepted 31 July 2014 studies. Case studies of men who have committed sexual offences against children implicate frontal Available online 10 August 2014 and temporal abnormalities that may be associated with impaired impulse inhibition. Structural neuroimaging investigations show volume reductions in paedophilic men. Although the findings have Keywords: been heterogeneous, smaller amygdala volume has been replicated repeatedly. Functional neuroimaging Child sexual abuse investigations demonstrate an overlap between paedophiles and teleiophiles during sexual arousal Sexual arousal processing. While it is controversial among studies regarding group differences, reliable discrimination Sexual offending Brain pathology between paedophilic and teleiophilic men may be achieved using functional activation patterns. Magnetic resonance imaging Nevertheless, the heterogeneous findings published so far suggest further research is necessary to disentangle the neurobiological mechanisms of paedophilic preference. A number of methodological confounds have been identified, which may account for the inconsistent results that could prove to be beneficial for future investigations. ß 2014 Elsevier Ltd. All rights reserved. Contents 1. Introduction . 2 1.1. Diagnosis . 2 1.2. Prevalence . 2 1.3. Paedophilia vs. sexual offending against children . 3 1.4. Aetiology . 4 1.5. The neurophenomenological model of sexual arousal . 4 1.6. Literature search . 4 Abbreviations: ICD-10, International Classification of Diseases and Related Health Problems, 10th Revision, World Health Organization; DSM-5, Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, American Psychiatric Association; CSA, child sexual abuse; CSO, child sexual offender; NSO, non-sexual offender; MRI, magnetic resonance imaging; fMRI, functional magnetic resonance imaging; PET, positron emission tomography; CT, computed tomography; VBM, voxel-based morphometry; ROI, region of interest; FWE, familywise error; FDR, false discovery rate. * Corresponding author at: Charite´ – Universita¨tsmedizin Berlin, Campus Mitte, Department of Psychiatry and Psychotherapy, Division of Mind and Brain Research, Charite´platz 1, 10117 Berlin, Germany. Tel.: +49 30 450 517 223; fax: +49 30 450 517 906. ** Corresponding author at: Charite´ – Universita¨tsmedizin Berlin, Campus Mitte, Department of Psychiatry and Psychotherapy, Division of Mind and Brain Research, Charite´platz 1, 10117 Berlin, Germany. Tel.: +49 30 450 517 141; fax: +49 30 450 517 906. E-mail addresses: [email protected] (S. Mohnke), [email protected] (S. Mu¨ ller), [email protected] (T. Amelung), [email protected] (Tillmann H.C. Kru¨ ger), [email protected] (J. Ponseti), [email protected] (B. Schiffer), [email protected] (M. Walter), [email protected] (K.M. Beier), [email protected] (H. Walter). http://dx.doi.org/10.1016/j.pneurobio.2014.07.005 0301-0082/ß 2014 Elsevier Ltd. All rights reserved. 2 S. Mohnke et al. / Progress in Neurobiology 122 (2014) 1–23 2. Neurological case reports . 5 2.1. Brain tumours . 5 2.2. Different forms of dementias . 7 2.3. Parkinson’s disease . 7 2.4. Further neurological disorders . 8 3. Neuroimaging . 8 3.1. Structural neuroimaging. 8 3.1.1. CT studies. 8 3.1.2. MRI studies . 8 3.2. Functional neuroimaging . 12 3.2.1. PET studies. 12 3.2.2. fMRI studies. 12 3.3. Correlational analyses in neuroimaging studies . 18 4. Discussion . 19 Acknowledgements . 22 References . 22 1. Introduction et al., 2013), implying that the sexual interest in prepubertal children would be distinguishable from the sexual interest in 1.1. Diagnosis pubertal children. Contrary to early propositions, and after an extensive debate, the diagnosis of hebephilia was not included in Paedophilia is commonly viewed as an adult sexual responsive- the DSM-5 (for a summary of this discussion see Blanchard, 2013). ness towards immature (prepubescent) subjects. Research distin- In addition, the ICD-10 requires the presence of recurrent sexual guishes it from teleiophilia as the sexual responsiveness to mature fantasies or urges towards children, and these elements are not (postpubertal) subjects and hebephilia, the sexual responsiveness necessary according to the DSM-5. Following DSM-criteria sexual to pubertal children (Beier et al., 2013; Blanchard et al., 2000). behaviour with prepubescent children that persists more than six Paedophilia appears in both psychiatric diagnostic systems, the months would be sufficient for the diagnosis of paedophilic ICD-10 and the DSM-5, under disorders of sexual preference disorder, even in the absence of arousing fantasies or urges. (paraphilia). Since the DSM-5, paedophilia is explicitly distin- The DSM-5 distinguishes between an exclusive and a non- guished from paedophilic disorder, defined via recurrent, intense exclusive type of paedophilia (whether the person can be sexually sexually arousing fantasies, and sexual urges towards prepubes- aroused only by children or also by elder persons), a gender cent children. The latter additionally requires either that these preference, and a limitation to incest. Also, the criteria within each sexual urges lead to marked distress, interpersonal difficulty, or diagnostic system have been changed significantly during its that the individual has acted out on these sexual urges. Therefore, development (for DSM criteria, see Blanchard, 2010). Therefore, by the redefinition of the term paedophilia (i.e., sexual focus on the different definitions of paedophilia comprise different popula- children without distress, interpersonal difficulty, and sexual acts tions that have a common intersecting-set but are not identical involving children), the mere sexual preference for children has (see Fig. 1). been depathologized. This makes sense from both a clinical and a The stability of paedophilia is also controversial. In general, forensic perspective, since paedophilia which causes neither paedophilia has been seen as a lifelong individual trait (e.g., Seto, suffering nor child harm requires no therapy or prosecution 2008, 2012). Cases in which paedophilic behaviours occurred after (although preventive measures could be indicated, because the brain lesions have thus been discussed as behavioural manifesta- preference may still constitute a risk factor for later offending; see tions of pre-existent latent paedophilic urges due to general Section 1.3). impulse disinhibition. In contrast, there are some reports claiming Both ICD-10 and DSM-5 require that the affected person’s successful therapeutic alteration of sexual preference and reduced sexual urges/fantasies have been acted upon or cause marked reoffending in paedophilic child sexual offenders (CSO; Marshall distress or interpersonal difficulty. Furthermore, both systems et al., 2005; Marshall, 2008). Additionally, a change in psycho- specify that the affected person must be 16 years and at least five physiological reaction to child sexual stimuli has been recently years older than the sexually desired children. In contrast to the demonstrated in some men (Mu¨ ller et al., 2014). Whether the ICD-10, the DSM-5 further specifies that individuals in late changes reported represent an ‘‘elimination’’ of paedophilia or adolescence who are in ongoing sexual relationships with 12– rather a control of symptoms remains unclear. While the findings 13-year-olds do not fit the criteria for paedophilia. Further remain anecdotal, they might still challenge the state of the art disagreement between the diagnostic systems exists with regard view of paedophilia as a stable and unchangeable condition. to the (body) age of the desired children: ICD-10 defines Neurobiological correlates may be particularly useful to disentan- paedophilia (F65.4) as a sexual preference for children who are gle whether paedophilia is mutable by: first, elucidating the either prepubescent or in an early state of puberty, but might also aetiology