Leonardo F. Fontenelle has been a prolific writer in the field of obsessive-compulsive and related disorder for almost twenty years. He is a Professor at the Federal University of Rio de Janeiro, D'Or Institute for Research and Education, and Monash Institute of Cognitive and Clinical Neurosciences. Murat Yücel has studied addiction and OCD for two decades and is a recognised expert in the area of biological psychiatry and addiction neuroscience. He is a Professorial Fellow at Monash University, Victoria and a Principal Research Fellow within the National Health and Medical Research Council of Australia.

'Top researchers from across the world have contributed to making A Transdiagnostic Approach to Obsessions, Compulsions and Related Phenomena the most comprehensive text published on this topic. The book, which is backed by the latest academic literature, provides a wide-ranging approach to treatment that incorporates psychopathologic, neurobiological, clinical and therapeutic elements. Obsessive-compulsive disorder and associated mental illnesses can be difficult to diagnose. The book provides immense value in providing clinicians and researchers alike with the nuances necessary to identify and help patients to the best extent possible. It will undoubtedly be an indispensable reference document for professionals in this field for years to come.' Antonio E. Nardi, Universidade Federal do Rio de Janeiro, Brazil

• 1. A transdiagnostic approach to obsessions, compulsions and related phenomena Leonardo F. Fontenelle and Murat Yücel; 2. The philosophy of compulsive disorders: compulsivity and free will Judy Luigjes and Damiaan Denys; 3. Family and twin studies of obsessive-compulsive and related disorders Danielle C. Cath, Nuno R. Zilhão, Dirk J. A. Smit and Dorret I. Boomsma; 4. The molecular genetics of obsessive-compulsive and related disorders Fabiana Barzotti Kohlrausch; 5. The role of environmental factors in the pathogenesis of obsessive-compulsive and related disorders Catarina Raposo-Lima and Pedro Morgado; 6. Immunology of obsessive-compulsive and related disorders Antonio L. Teixeira, Natalia P. Rocha and Andrea H. Marques; 7. Neurocognitive basis of compulsivity Martijn Figeea, Judy Luigjes, Anneke Goudriaan, Ingo Willuhnb and Damiaan Denys; 8. Structural brain imaging of obsessive-compulsive and related disorders Carles Soriano-Mas and Ben J. Harrison; 9. fMRI studies of obsessive-compulsive and related disorders Jaewook Han and Jun Soo Kwon; 10. Epidemiology of obsessive-compulsive disorder Roselind Lieb, Patrizia Hofer and Karina Wahl; 11. Symptoms, diagnosis and specifiers of obsessive-compulsive disorder Leonardo F. Fontenelle; 12. The natural history of obsessive-compulsive disorder across the lifespan Eesha Sharma and Y. C. Janardhan Reddy; 13. Subdiagnostic obsessive-compulsive disorder symptoms Albina R. Torres and Leonardo F. Fontenelle; 14. Assessment instructions for obsessive-compulsive disorder Andrew G. Guzick, Adam M. Reid and Eric A. Storch; 15. Pharmacological treatments for obsessive compulsive and related disorders – a transdiagnostic perspective Ricky A Sachdev, Risha Ruparelia, Jemma E. Reid, Davis Mpavenda, Eduardo Cinosi and Naomi A Fineberg; 16. Psychological treatment of OCD: efficacy, mechanisms and transdiagnostic implications Jennifer L. Buchholz, Lillian Reuman, Shannon M. Blakey and Jonathan S. Abramowitz; 17. Innovative cognitive-behavioural treatments for obsessive-compulsive disorder K. P. O'Connor, C. Ouellet-Courtois and F. Aardema; 18. Drug augmentation strategies for treatment-resistant obsessive-compulsive disorder and obsessive-compulsive related disorders Roseli Gedanke Shavitt and Juliana Belo Diniz; 19. Integrating cognitive behavioral treatment and medications for the treatment of obsessive compulsive disorder Yael R. Stovezky, Marina Gershkovich, Reilly Kayser and H. Blair Simpson; 20. DBS, TMS and tDCS for obsessive-compulsive disorder Rebecca A. Segrave, Joshua J. Hendrikse and Linden Parkes; 21. Neurosurgery for obsessive-compulsive disorder: indications and procedures Antonio Carlos Lopes; 22. Alternative treatments for obsessive-compulsive disorder: nutraceuticals and lifestyle interventions Jerome Sarris and Georgina Oliver; 23. Transdiagnostic and unique clinical and treatment factors of dysmorphophobia: body dysmorphic disorder and olfactory reference disorder Francesca Beilharz and Susan L Rossell; 24. Hypochondriasis Vladan Starcevic; 25. Hoarding disorder Lorena Fernández de la Cruz and David Mataix-Cols; 26. Transdiagnostic factors in obsessive compulsive personality disorder Michael G. Wheaton and Anthony Pinto; 27. Tourette syndrome and other tic disorders Andrea E. Cavanna; 28. Body-focused repetitive behaviors Jon E. Grant and Samuel R. Chamberlain; 29. Stereotypic movement disorder Dan J. Stein; 30. The clinical neuropsychiatry of 'organic' obsessive-compulsive disorder Leonardo F. Fontenelle; 31. Behavioral addictions Samuel R. Chamberlain and Jon E. Grant; 32. Other obsessive-compulsive related disorders Ygor Arzeno Ferrão.

Leonardo F. Fontenelle has been a prolific writer in the field of obsessive-compulsive and related disorder for almost twenty years. He is a Professor at the Federal University of Rio de Janeiro, D'Or Institute for Research and Education, and Monash Institute of Cognitive and Clinical Neurosciences. Murat Yücel has studied addiction and OCD for two decades and is a recognised expert in the area of biological psychiatry and addiction neuroscience. He is a Professorial Fellow at Monash University, Victoria and a Principal Research Fellow within the National Health and Medical Research Council of Australia.

'Top researchers from across the world have contributed to making A Transdiagnostic Approach to Obsessions, Compulsions and Related Phenomena the most comprehensive text published on this topic. The book, which is backed by the latest academic literature, provides a wide-ranging approach to treatment that incorporates psychopathologic, neurobiological, clinical and therapeutic elements. Obsessive-compulsive disorder and associated mental illnesses can be difficult to diagnose. The book provides immense value in providing clinicians and researchers alike with the nuances necessary to identify and help patients to the best extent possible. It will undoubtedly be an indispensable reference document for professionals in this field for years to come.' Antonio E. Nardi, Universidade Federal do Rio de Janeiro, Brazil

• 1. A transdiagnostic approach to obsessions, compulsions and related phenomena Leonardo F. Fontenelle and Murat Yücel; 2. The philosophy of compulsive disorders: compulsivity and free will Judy Luigjes and Damiaan Denys; 3. Family and twin studies of obsessive-compulsive and related disorders Danielle C. Cath, Nuno R. Zilhão, Dirk J. A. Smit and Dorret I. Boomsma; 4. The molecular genetics of obsessive-compulsive and related disorders Fabiana Barzotti Kohlrausch; 5. The role of environmental factors in the pathogenesis of obsessive-compulsive and related disorders Catarina Raposo-Lima and Pedro Morgado; 6. Immunology of obsessive-compulsive and related disorders Antonio L. Teixeira, Natalia P. Rocha and Andrea H. Marques; 7. Neurocognitive basis of compulsivity Martijn Figeea, Judy Luigjes, Anneke Goudriaan, Ingo Willuhnb and Damiaan Denys; 8. Structural brain imaging of obsessive-compulsive and related disorders Carles Soriano-Mas and Ben J. Harrison; 9. fMRI studies of obsessive-compulsive and related disorders Jaewook Han and Jun Soo Kwon; 10. Epidemiology of obsessive-compulsive disorder Roselind Lieb, Patrizia Hofer and Karina Wahl; 11. Symptoms, diagnosis and specifiers of obsessive-compulsive disorder Leonardo F. Fontenelle; 12. The natural history of obsessive-compulsive disorder across the lifespan Eesha Sharma and Y. C. Janardhan Reddy; 13. Subdiagnostic obsessive-compulsive disorder symptoms Albina R. Torres and Leonardo F. Fontenelle; 14. Assessment instructions for obsessive-compulsive disorder Andrew G. Guzick, Adam M. Reid and Eric A. Storch; 15. Pharmacological treatments for obsessive compulsive and related disorders – a transdiagnostic perspective Ricky A Sachdev, Risha Ruparelia, Jemma E. Reid, Davis Mpavenda, Eduardo Cinosi and Naomi A Fineberg; 16. Psychological treatment of OCD: efficacy, mechanisms and transdiagnostic implications Jennifer L. Buchholz, Lillian Reuman, Shannon M. Blakey and Jonathan S. Abramowitz; 17. Innovative cognitive-behavioural treatments for obsessive-compulsive disorder K. P. O'Connor, C. Ouellet-Courtois and F. Aardema; 18. Drug augmentation strategies for treatment-resistant obsessive-compulsive disorder and obsessive-compulsive related disorders Roseli Gedanke Shavitt and Juliana Belo Diniz; 19. Integrating cognitive behavioral treatment and medications for the treatment of obsessive compulsive disorder Yael R. Stovezky, Marina Gershkovich, Reilly Kayser and H. Blair Simpson; 20. DBS, TMS and tDCS for obsessive-compulsive disorder Rebecca A. Segrave, Joshua J. Hendrikse and Linden Parkes; 21. Neurosurgery for obsessive-compulsive disorder: indications and procedures Antonio Carlos Lopes; 22. Alternative treatments for obsessive-compulsive disorder: nutraceuticals and lifestyle interventions Jerome Sarris and Georgina Oliver; 23. Transdiagnostic and unique clinical and treatment factors of dysmorphophobia: body dysmorphic disorder and olfactory reference disorder Francesca Beilharz and Susan L Rossell; 24. Hypochondriasis Vladan Starcevic; 25. Hoarding disorder Lorena Fernández de la Cruz and David Mataix-Cols; 26. Transdiagnostic factors in obsessive compulsive personality disorder Michael G. Wheaton and Anthony Pinto; 27. Tourette syndrome and other tic disorders Andrea E. Cavanna; 28. Body-focused repetitive behaviors Jon E. Grant and Samuel R. Chamberlain; 29. Stereotypic movement disorder Dan J. Stein; 30. The clinical neuropsychiatry of 'organic' obsessive-compulsive disorder Leonardo F. Fontenelle; 31. Behavioral addictions Samuel R. Chamberlain and Jon E. Grant; 32. Other obsessive-compulsive related disorders Ygor Arzeno Ferrão.

Leonardo F. Fontenelle has been a prolific writer in the field of obsessive-compulsive and related disorder for almost twenty years. He is a Professor at the Federal University of Rio de Janeiro, D'Or Institute for Research and Education, and Monash Institute of Cognitive and Clinical Neurosciences. Murat Yücel has studied addiction and OCD for two decades and is a recognised expert in the area of biological psychiatry and addiction neuroscience. He is a Professorial Fellow at Monash University, Victoria and a Principal Research Fellow within the National Health and Medical Research Council of Australia.

'Top researchers from across the world have contributed to making A Transdiagnostic Approach to Obsessions, Compulsions and Related Phenomena the most comprehensive text published on this topic. The book, which is backed by the latest academic literature, provides a wide-ranging approach to treatment that incorporates psychopathologic, neurobiological, clinical and therapeutic elements. Obsessive-compulsive disorder and associated mental illnesses can be difficult to diagnose. The book provides immense value in providing clinicians and researchers alike with the nuances necessary to identify and help patients to the best extent possible. It will undoubtedly be an indispensable reference document for professionals in this field for years to come.' Antonio E. Nardi, Universidade Federal do Rio de Janeiro, Brazil

• 1. A transdiagnostic approach to obsessions, compulsions and related phenomena Leonardo F. Fontenelle and Murat Yücel; 2. The philosophy of compulsive disorders: compulsivity and free will Judy Luigjes and Damiaan Denys; 3. Family and twin studies of obsessive-compulsive and related disorders Danielle C. Cath, Nuno R. Zilhão, Dirk J. A. Smit and Dorret I. Boomsma; 4. The molecular genetics of obsessive-compulsive and related disorders Fabiana Barzotti Kohlrausch; 5. The role of environmental factors in the pathogenesis of obsessive-compulsive and related disorders Catarina Raposo-Lima and Pedro Morgado; 6. Immunology of obsessive-compulsive and related disorders Antonio L. Teixeira, Natalia P. Rocha and Andrea H. Marques; 7. Neurocognitive basis of compulsivity Martijn Figeea, Judy Luigjes, Anneke Goudriaan, Ingo Willuhnb and Damiaan Denys; 8. Structural brain imaging of obsessive-compulsive and related disorders Carles Soriano-Mas and Ben J. Harrison; 9. fMRI studies of obsessive-compulsive and related disorders Jaewook Han and Jun Soo Kwon; 10. Epidemiology of obsessive-compulsive disorder Roselind Lieb, Patrizia Hofer and Karina Wahl; 11. Symptoms, diagnosis and specifiers of obsessive-compulsive disorder Leonardo F. Fontenelle; 12. The natural history of obsessive-compulsive disorder across the lifespan Eesha Sharma and Y. C. Janardhan Reddy; 13. Subdiagnostic obsessive-compulsive disorder symptoms Albina R. Torres and Leonardo F. Fontenelle; 14. Assessment instructions for obsessive-compulsive disorder Andrew G. Guzick, Adam M. Reid and Eric A. Storch; 15. Pharmacological treatments for obsessive compulsive and related disorders – a transdiagnostic perspective Ricky A Sachdev, Risha Ruparelia, Jemma E. Reid, Davis Mpavenda, Eduardo Cinosi and Naomi A Fineberg; 16. Psychological treatment of OCD: efficacy, mechanisms and transdiagnostic implications Jennifer L. Buchholz, Lillian Reuman, Shannon M. Blakey and Jonathan S. Abramowitz; 17. Innovative cognitive-behavioural treatments for obsessive-compulsive disorder K. P. O'Connor, C. Ouellet-Courtois and F. Aardema; 18. Drug augmentation strategies for treatment-resistant obsessive-compulsive disorder and obsessive-compulsive related disorders Roseli Gedanke Shavitt and Juliana Belo Diniz; 19. Integrating cognitive behavioral treatment and medications for the treatment of obsessive compulsive disorder Yael R. Stovezky, Marina Gershkovich, Reilly Kayser and H. Blair Simpson; 20. DBS, TMS and tDCS for obsessive-compulsive disorder Rebecca A. Segrave, Joshua J. Hendrikse and Linden Parkes; 21. Neurosurgery for obsessive-compulsive disorder: indications and procedures Antonio Carlos Lopes; 22. Alternative treatments for obsessive-compulsive disorder: nutraceuticals and lifestyle interventions Jerome Sarris and Georgina Oliver; 23. Transdiagnostic and unique clinical and treatment factors of dysmorphophobia: body dysmorphic disorder and olfactory reference disorder Francesca Beilharz and Susan L Rossell; 24. Hypochondriasis Vladan Starcevic; 25. Hoarding disorder Lorena Fernández de la Cruz and David Mataix-Cols; 26. Transdiagnostic factors in obsessive compulsive personality disorder Michael G. Wheaton and Anthony Pinto; 27. Tourette syndrome and other tic disorders Andrea E. Cavanna; 28. Body-focused repetitive behaviors Jon E. Grant and Samuel R. Chamberlain; 29. Stereotypic movement disorder Dan J. Stein; 30. The clinical neuropsychiatry of 'organic' obsessive-compulsive disorder Leonardo F. Fontenelle; 31. Behavioral addictions Samuel R. Chamberlain and Jon E. Grant; 32. Other obsessive-compulsive related disorders Ygor Arzeno Ferrão.