Open AcceReviewObsessive-compulsive disorder and related disorders: a comprehensive surveyMichele Fornaro*1, Filippo Gabrielli1, Claudio Albano2, Stefania Fornaro3, Salvatore Rizzato4, Chiara Mattei1, Paola Solano1, Valentina Vinciguerra1 and Pantaleo Fornaro1
Address: 1Dipartimento di Neuroscienze, Oftalmologia e Genetica (DINOG), Sezione di Psichiatria, Università di Genova, Genova, Italy, 2Dipartimento di Neuroscienze, Oftalmologia e Genetica (DINOG), Sezione di Neurologia, Università di Genova, Genova, Italy, 3Dipartimento di Neuroscienze, Sezione di Medicina Legale, Università di Pisa, Pisa, Italy and 4Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Sezione di Psichiatria, Università di Pisa, Pisa, Italy
AbstractOur aim was to present a comprehensive, updated survey on obsessive-compulsive disorder(OCD) and obsessive-compulsive related disorders (OCRDs) and their clinical management vialiterature review, critical analysis and synthesis.
Information on OCD and OCRD current nosography, clinical phenomenology and etiology, maylead to a better comprehension of their management. Clinicians should become familiar with thebroad spectrum of OCD disorders, since it is a pivotal issue in current clinical psychiatry.
IntroductionObsessive-compulsive disorder (OCD) is a common,chronic, anxiety condition that can have disabling effectson both genders throughout the patient's lifespan. OCDcan manifest with a wide range of clinical pictures [1].
The disorder is among the most disabling anxiety condi-tions and counts for more than half of serious anxietycases [2]. However, no univocal clinical opinion existsabout its classification. In fact, although the Diagnosticand Statistical Manual of Mental Disorders, 4th edition –text revision (DSM-IV-TR) [3] classifies OCD as an anxietydisorder, some clinicians conceptualize it as a spectrum ofrelated disorders (OCRDs) sharing the 'anxiety/fear' cou-pled with 'worry' clinical feature [4,5].
The broad spectrum of OCRDs includes the somatoformdisorders (for example, body dysmorphic disorder (BDD)and hypochondriasis), the impulse-control disorders (forexample, trichotillomania (TTM), pathological gambling,skin picking and others) and the tic disorders (for exam-ple, Tourette's syndrome) but others, including drug-induced and non-psychiatric disorders, could overlap andshow similar clinical pictures [6]. The National Comor-bidity Survey Replication study reported more than aquarter of evaluated subjects developing obsessions andcompulsions at some point in their life and possibly man-ifesting with a full-threshold OCD, while a higher numberof patients will probably suffer from OCRDs [2].
Published: 18 May 2009
Annals of General Psychiatry 2009, 8:13 doi:10.1186/1744-859X-8-13
Received: 22 December 2008Accepted: 18 May 2009
This article is available from: http://www.annals-general-psychiatry.com/content/8/1/13
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The most common age of onset of OCD is reported to bebetween 22 and 35, while affected patients spend an aver-age of 17 years before receiving a correct diagnosis andtreatment, with most OCD and OCRDs often showing awaxing and waning course, frequently increasing in sever-ity when left untreated [7,8].
Further increasing the burden of OCD is the fact thataffected subjects, along with many psychiatric patients,often experience discrimination and stigmatization due toa non-medical perception of the phenomenon. Yet OCDand OCRDs represent relevant medical conditions. Find-ings provided by recent studies, mainly focusing on therole played by the amygdala and its links to the 'fear cir-cuits' and other structural and functional abnormalities ofseveral corticostriatal pathways, also indicate a relation-ship between OCD manifestations and its neurobiologi-cal basis, suggesting new therapeutic strategies [9].
Treatment of OCD typically involves the use of medica-tions in combination with other modalities (such as cog-nitive behavioural therapy (CBT), psychoeducation andsupport groups and so on): first line treatments optionsinclude both serotonin reuptake inhibitors (SRIs) medica-tion and CBT [10], but anxiolitics and antipsychotics,among other classes of drugs, are used as well. Finally, theidentification of OCD and its appropriate treatment isessential to improve the quality of assistance and toreduce the waste of health care resources through unnec-essary medical care.
Historical background and current nosographyObsessions thoughts and compulsive urges or actions arepart of everyday life. We return to check that we locked adoor and switched off the light. We cannot stop thinkingabout the stressful event scheduled for the next week. Werefuse to eat with the spoon that dropped on the floor,even if we know the chance of contamination is remote.
These events are part of the normal feedback and controlloop between our thoughts and our actions, and they havean ancestral biological survival value. It is only whenobsessive thoughts become frequent or intense, or una-voidable, or when these compulsive rituals become soprominent that they interfere with an individual's func-tioning, that the diagnosis of OCD is made.
Descriptions of the phenomena of obsessions and com-pulsions can be found in historical documents over thepast several centuries, since OCD has a long history. A pas-sage from the Malleus Maleficarum, the 15th century com-pendium of witchcraft and psychopathology, describes apriest brought to Rome for exorcism:
' [w]hen he passed any church, and genuflected in honourof the Glorious virgin, the devil made him thrust histongue far out of his mouth when he tried to engage inprayer, [the devil] attacked him more violently' [11].
Those with obsessive thoughts of a blasphemous or sexualnature were thought to be partially possessed by the devil,while 'psychotic' individuals appeared fully possessed.Obsessions and hand-washing rituals resulting from guiltwere immortalized in the 17th century by the Shakespearecharacter Lady Macbeth:
'[...] it is an accustomed action with her, to seem thuswashing her hands. I have known her continue with this aquarter of an hour' (Macbeth, V.i.28, describing the time-wasting characteristic of OCD).
With time, the explanation for obsessions and compul-sions moved from a religious view to a medical one.Obsessions and compulsions were first described in thepsychiatric literature by Esquirol in 1838, and, by the endof the 19th century, they were generally regarded as man-ifestations of melancholy or depression. By the beginningof the 20th century, the view of obsessive-compulsivephenomena had begun to shift OCD toward a psycholog-ical explanation; Janet had already described the success-ful treatment of compulsive rituals with what would cometo be known behavioral techniques [12], and with Freud'spublication in 1909 of the psychoanalysis of a case ofobsessional neurosis (the Rat Man), obsessive and com-pulsive actions came to be seen as the results of uncon-scious conflicts and the isolation of thoughts and actionsfrom their emotional components [13]. Although thisshift succeeded in pointing out that actions can be moti-vated by factors of which the individual is unaware orunable to control, it did little to improve the outcome ofpatients OCD.
In the 1950s, with the rise of behavioral therapy, thelearning theories that had proved to be helpful in the con-ceptualization and treatment of phobic disorders wereapplied to OCD symptoms. Although these learning the-ories are clearly insufficient to account for all OCD (aswell as OCRD) symptoms, they did lead to the develop-ment in the late 1960s and early 1970s of effective treat-ments for reducing compulsive rituals. During the 1980s,research focused on the relationship of OCD and neuro-logical problems such as epilepsy [14], memory disordersand Tourette's syndrome [15] while Westphal's earlyobservation of an association between obsessions, tic dis-orders and epilepsy already presaged recent neurobiologi-cal findings in OCD.
OCD and OCRDs may also have common manifestationsand, since the 1990s, they have therefore been conceptu-
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alized with a broad spectrum of related disorders [16](Figure 1) [17].
The 1994 DSM-IV operated a split between the phobic/anxious-avoidant and obsessive dimensions, categorizedby the previous DSM-III (1980) and its 1987 revised edi-tion (DSM-III-R) with the unitary diagnosis of 'phobic-obsessive disorder' [18]. The current DSM-IV-TR describesOCD as characterized by repetitive thoughts, images,impulses that intrude on a patient unable to stop them[3].
Current nosology underlines the following three majorsymptom clusters for OCD and OCRDs: a 'somatic' clusterfor BDD and hypocondriasis, a 'reward deficiency' clusterfor TTM and other impulse control disorders (ICDs), andan 'impulsivity' one for kleptomania, compulsive shop-ping (CS), pathological gambling (PG), intermittentexplosive disorder (IED) and others [19].
While most psychiatrists generally agree on the OCD spec-trum including anxious and phobic manifestations, agreater number also focus on the need of a clear-cut defi-nition of anxious and obsessive symptoms, as is antici-pated by the research agenda for DSM-V[5]. In fact,anxious phobia differs from OCD. Both phobic andobsessive-compulsive subjects usually avoid fearedobjects and generally retain awareness their fears andavoidance behaviors are excessive. Phobics are usuallymore upset about the prospect of actually coming intocontact with the thing they fear and do what they can toavoid it, while OCD patients may be more concernedabout the time-consuming rituals such contacts will trig-ger, rather than fear of the contact itself.
EpidemiologyObsessive and compulsive symptoms are common andnot all of them may be accounted for a full-thresholdOCD. Approximately 50% of the general populationengage in some ritualized behaviors, while up to 80%experience intrusive, unpleasant or unwanted thoughts[20].
The 1 month prevalence of adult OCD is about 0.6% [21]while the DSM-IV 12 month prevalence ranges from 0.6%to 1%. Regardless, the prevalence of OCD, as well OCRDs,may vary depending on the source of data and the choiceof diagnostic instruments. Many OCRDs may co-occurwith each other and with OCD. With regard to thesomatoform disorders, the estimated prevalence rate ofhypochondriasis is 1% to 5% in the general populationand 2% to 7% among primary care outpatients. Unfortu-nately, the prevalence rate of BDD is difficult to estimategiven the secrecy of this severe condition [22], but esti-mates range from 0.7% to 2.3% in the general population
and at least from 6% to 15% in cosmetic surgery settings[23]. For OCRDs the prevalence of Tourette's is 0.1%,while the exact lifetime prevalence of TTM is unknown,but rates from 1% to 2% have been reported for cases thatsatisfy the full threshold diagnostic criteria [24].
There seems to be a bimodal age of onset for OCD. Themean onset has been reported to be 19 years (21% of thecases emerged at age 10), while the mean age for adultOCD occurs between age 22 and 35. In a small number ofcases the onset of the disorder occurs at age of 50 or more[2]. Usually, the earlier the age of onset, the worse thecourse of OCD and OCRDs; by contrast, no specific gen-der predominance has been reported in large samples epi-demiological studies. This latter evidence is in contrastwith non-OCD anxiety conditions whose gender ratiosusually indicate a prevalence of female cases [25].
While economic, social and cultural effects may play arole in producing different clinical pictures of OCD, bio-logical, immune and genetic factors and family predispo-sition may also contribute to the pathogenesis of thedisorder. For example, streptococcal infection may beassociated with an abrupt, exacerbating-remitting early-onset form of OCD, which is termed pediatric autoim-mune disorder associated with streptococcus (PANDAS),but little is known about this condition, and in particularabout the genesis of this OCRD [26].
OCD's burden may also vary depending on the case inquestion, on the course of disorder and on the fact it isalmost unknown among the general population. As a con-sequence, many patients do not seek medical care until(originally) milder forms of OCD and OCRDs becomemore distressful and possibly harder to treat. Further-more, a large number of obsessive-compulsive conditionsmay go under-diagnosed: studies have placed the preva-lence between 1% and 3% of OCD cases, although theprevalence of clinically recognized OCD is probablymuch lower [2].
The fact that many individuals do not seek early appropri-ate treatments may be due to stigma, but also to other fac-tors. Sometimes patients do not realize that they areaffected by OCD. In some cases, the 'typically obsessive'features of intrusive, 'ego-dystonic' feelings and thoughtsare absent, as in the poor-insight obsessive-compulsivedisorder (PI-OCD), complicating the course and severityof the illness [27]. Including PI-OCD and other subtypesextends the range of OCD cases that are reported to afflictapproximately 2% to 3% of the world's population; theseshow varying degrees of severity and chronic course andoften also include depressive feelings (80%), majordepression (MD) comorbidity (30%) and Tourette's syn-drome comorbidity (5%).
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The current spectrum of obsessive-compulsive disorder (OCD) and related disorders (OCRDs)Figure 1The current spectrum of obsessive-compulsive disorder (OCD) and related disorders (OCRDs). Adapted from Roan WM et al. [17].
Y n o P T [ S p Q X q Z N Q M Z T e [ U W g Q M Z N
Y ] ^ P Y ] ^ [ X U W V \ T R U M N [ W
r s P W X M N [ m Q W X [ N g M T W
r T ` P r T ` [ N j [ N \ T T ] X ^ N M V [
r Y h l P W X O Q T M R Q W S ` [ N T M X W S Q O ] ^ Q T M N ^ [ N
r Z O P W Z O Q T V
o s P e Z S Q V Q W
o i P e W T W S j W X j S Q W ^ Q T M N ^ [ N
o l l P e M ^ ] ^ ] T V M N ` U Q R ^ Q T M N ^ [ N
l [ S d k l P ^ [ S Z T Q M X W S d k l
l [ ` P ^ [ ` [ N T M X W S Q f W O Q M X l Q T M N ^ [ N
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Additionally, OCD patients usually present symptomssimilar to those of their affected relatives. About 8% offirst degree relatives have OCD, while first symptomsoccur by their 20s in 75% of the patients; this may happensuddenly or slowly, generally showing an episodic course[28]. Interestingly, the episodic course is sometimes anoverlap feature of the illness with MD, but it may alsoprompt clinicians to explore other affective comorbiditiesas well [29], and we urge for more vigilance for largelyunder-recognized entities such as cyclothymic-OCD [30].
For example, a small number of very severe OCD casesmay also develop suicidal ideations or behaviors, as thepatient could be perceive suicide as the only possibility ofescape from their tremendous pain. In such patients, acommon neurobiological and genetic basis has beenhypothesized to be responsible for depressive suicidalbehaviors and for severe ego-dystonic obsessive manifes-tations. Such a hypothesis has also been supported by theex adiuvantibus findings of similar pharmacotherapeuticstrategies being effective in both pathological dimensions.
Diagnostic criteriaThe main features of OCD are the obsessions and compul-sions. According to DSM-IV-TR, the obsessions and com-pulsions cause marked distress, are time-consuming(usually taking more than 1 h per day for a month ormore) and significantly impair the normal functioning ofthe subject. If another Axis I disorder is present, it is man-datory that the content of the obsessions or compulsionsnot be restricted to it (for example, preoccupation withfood or weight in eating disorders or guilt ruminations inthe presence of a major depressive episode (MDE)). Thedisturbance should not be due to the direct effects of asubstance (for example, drug or medication abuse), or ageneral medical condition (Figure 2).
Obsessions may also manifest with very heterogeneousclinical pictures (for example, religious scrupulosity,aggressive or intrusive thoughts, inappropriate sexualthoughts, concerns about symmetry and perfectionism,pathological doubt, contamination worries, pathologicalcollecting and hoarding), while compulsions are definedas repetitive behaviors or mental acts (for example, wash-ing, counting, checking, ordering, touching, cleaning,hoarding, conducting mental or physical rituals).
Obsessions are usually unwanted, unavoidable, intrusive,ego-dystonic, occasionally frightening or violent (forexample, the impulse to leap before a car, the thought thatyou may attack your spouse, that the pateint may molesta child) and often impair functioning and quality of life(QoL) [31].
It is remarkable that most OCD patients do criticize theirown thoughts and would hate to practice any by choice,yet in most cases they are unable to stop such thoughts orbehaviors. Nevertheless, OCD patients can ruminate end-lessly ('Did I lock the door?') and most of them develop(new) compulsions to ward off unwanted happenings orto satisfy obsessions (for example, an obsession with dirtleading to hand-washing rituals).
Differential diagnosis and clinical phenomenologyThe word 'obsession' derives from Latin 'obsidēre', whichmeans 'to take possession', 'to occupy'. In fact, most OCDpatients relate to the experience of a 'Middle ages fortressbesieged by strong enemies they have to surrender towithout any escape possibility'. The Latin word 'compellere'has the significance of 'to be constrained' and 'to be over-powered': OCD patients are forced to act on compulsionstrying to overcome obsessions.
Most OCD patients present both, but occasionally theycan manifest only obsessions or compulsions; this is suf-ficient for OCD diagnosis regardless.
Up to 20% of severe depression cases present obsessivesymptoms and treatment maybe identical while schizo-phrenics often show bizarre rituals they are usually com-fortable with, as in schizo-obsessive disorder (SOD)which neurological soft signs (NSS) psychopathology sug-gests is a severe form of OCRD [32-34].
Differential diagnosis is also a concern due to currentOCD and OCRD classification methods. People some-times wonder if compulsive eating, gambling, shoppingor deviant sexual behaviors are forms of OCRD. Usually,these disorders are not classified as OCRDs because somepleasure is obtained by these activities and the personwould not, ordinarily, wish to stop them except for thesecondary problems they may cause (such as obesity, con-victions for driving while intoxicated, gambling and creditcard debts and criminal prosecution for sexual deviancy).Nevertheless, few individuals with these compulsivebehaviors may respond to drug and behavioral treatmentsthat are effective for OCD [7].
Obsessions usually share an increasing 'anxious tension'before acting the compulsions (both behavioral and men-tal), followed by a brief sense of relief as they are carriedout. This kind of feeling is particularly evident in manyOCRDs too, as most eating disorders (EDs) may also beconsidered. In fact, many bulimia nervosa (BN) patientsexperience a brief reaction after binge eating while ano-rexia nervosa (AN) patients take a form of pleasure inbeing able to keep away from food.
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It is important to distinguish between obsessive-compul-sive symptoms in the course of EDs and OCD symptoms;a distinction should also be made for 'anxious' feelingsexperienced in the course of ICDs when the compulsion iscarried out.
Occasionally OCD thinking is bizarre, and patients couldeven exhibit schizotypical personality disorder (SPD)traits, usually being unaware of this (for example, 'Myspouse will leave me if I do not catch the elevator').
Since the OCD spectrum phenomenology may be varyheterogeneous, many rating scales and instruments, such
as the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS)and others also investigating OCRDs, have been devel-oped to help clinicians make diagnoses and to scoresymptoms, but clinical interview by a trained psychiatristshould not be discounted in any serious case [35].
Neurobiology and geneticsThere is growing evidence based on several lines ofresearch that OCD and OCRDs involve abnormal metab-olism in specific areas of the brain. Neuroimaging find-ings indicate OCD involves subtle structural andfunctional abnormalities of the orbito-frontal cortex(OFC), the anterior cingulate cortex (ACC), the caudate
Diagnostic and Statistical Manual of Mental Disorders, 4th edition – text revision (DSM-IV-TR) criteria for obsessive-compul-sive disorder (OCD)Figure 2Diagnostic and Statistical Manual of Mental Disorders, 4th edition – text revision (DSM-IV-TR) criteria for obsessive-compulsive disorder (OCD).
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nucleus (Cn), the amygdala nuclei (An), the accumbensnucleus (NAc), the cortical thalamic nuclei (Tn) as wellthe white matter (WM), the hippocampus (HP) and otherregions [36].
The OFC is involved with social consciousness regardingproper behavior. Hypoactivity in this area (whether occur-ring spontaneously or as a result of damage from a perina-tal or head injury, temporal lobe epilepsy, infection orbrain tumor and other conditions) leads to coarsening ofsocial consciousness and behaviors. This may lead tohypersexuality (paraphilic OCRDs), overeating behavior(EDs and Prader-Willi syndrome (PWS)), personalitychanges and Tourette's syndrome (frequently presentingwith inappropriate use of profanity) or crude jokes (sado-masochistic disorder (SMD)). Overactivity of the OFCmay results in excessive social concern, meticulousnessand 'nitpicking' habits, fastidiousness and avoidantbehaviors and more.
Other brain structures, such as the Cn, filter informationcoming from the forebrain, representing a sort of hub formany elaborate stimuli. It has been hypothesized that if'too many' messages regarding worries about 'how thingsshould be done' reach the Cn, they are not filtered prop-erly and spill over into (and flood) consciousness.Increased metabolism of the frontal part of the brain isconcerned with order and social proprierty. The Cn, alongwith other striatal structures, is also involved in regularrepetitive behaviors (rituals): the anterior caudatus puta-men (aCPu), the ACC directly leading to the shell of theNAc, the pallidus internus and the thalamus may play aspecific role in impulsive-repetitive psychic manifesta-tions of OCD and OCRDs (for example, the verbalTourette's symptoms).
Additionally, the dysregulation of the posterior caudatusputamen (pCPu) and the dorsolateral-prefrontal cortex(DL-PFC), the pallidus internus (PI) and the thalamusmay account for the neurological symptoms such as tics,Tourette's motor abnormalities and other OCD spectrummotor issues [32].
Both the striatal and the frontal brain areas are richly sup-plied with serotonergic neurons. It is not surprising thatmost OCD and OCRD drugs act as modulators for the ser-otonergic transmission in the central nervous system(CNS). However, even though 5-hydroxytryptamine (5-HT) is a core neurotransmitter involved in OCD andOCRD manifestations, this knowledge tells us little aboutthe ultimate causes or triggers of this psychopathology orabout effective treatments.
5-HT abnormalities may be the result of rather than causeof OCD and OCRD symptoms. Additionally, changes in
serotonergic transmission may have direct or indirecteffects on the neuronal firing of more than 60 other neu-romodulators affecting thoughts, feelings and behaviors.Thus, OCD is probably the final expression of many dif-ferent kinds of abnormalities in the structure and func-tioning of the brain. However, this complexity helps us tounderstand why some treatments are helpful while othersare not as effective. The 5-HT hypothesis was initiallymotivated by the observed differential efficacy of selectiveSRIs (SSRIs) in alleviating OCD symptoms. These find-ings, although attesting to the therapeutic versatility ofserotonin transporter inhibition in OCD, do not necessar-ily reflect the existence of neurobiological abnormality inthe central serotonergic system in OCD; a reasoningreferred to as an ex juvantibus argument [37]. There is alsogrowing evidence from both preclinical and clinical stud-ies that the dopamine (DA) system may be involved in thepathogenesis of OCD [38]. Studies on knockout (KO)mice for 5-HT2C receptor, already described as a model forobesity, showed increased chewing on non-nutritive claywith a distinct 'neat' pattern and a reduced habituation ofhead dipping activity as compared to the wild type, withthe conclusion that the 5-HT2C receptor null mutantmouse provides a putative model for compulsive behavior[39]. Tsaltas et al. have described a model based on per-sistence in the context of rewarded spatial alternation[40]. Using this behavior model, they have shown that 5-HT2C receptors are implicated in the mechanisms underly-ing the 'compulsive' behavior in this animal model forOCD. Acute administration of meta-chlorophenylpipera-zine (mCPP), a non-selective 5-HT receptor agonistmainly acting at the 5-HT2C receptors but with some affin-ity also for the 5-HT1B, 5-HT1A and α2-adrenergic recep-tors, increased 'compulsive' behavior [37]. The selective 5-HT1B receptor agonist naratriptan was not effective in thisanimal model, supporting the role of 5-HT2C receptorsunderlying the effect of mCPP [40]. On the basis of elec-trophysiological data, Joel and Doljansky suggested thatcompulsive lever-pressing depends on a phasic decreasein stimulation of D1 receptor [41]. In a pharmacologicalanimal model for OCD, in which rats are chronicallytreated with the selective D2/D3 receptor agonist quin-pirole (QNP), a ritual-like set of behavioral acts resem-bling OCD checking behavior, has been observed [42].This 'compulsive' behavior depends on QNP administra-tion, because it rapidly returns to normal behavior whenQNP administration is discontinued [43]. Postmortemanalysis in these animals revealed increased DA tissue lev-els in the NAc and right-PFC. The DL-PFC enables tempo-ral information processing and holding relevantinformation online [44]. It is believed to mediate workingmemory and executive functions. The basal ganglia arethought to project back to these cortical areas though themedial dorsal and anterior nuclei of the thalamus [45].
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A great amount of literature evidence reports OCD andOCRD to show an inherited transmission. Some familieshave at least four successive generations with clear OCDcases [46]. Since family members could have 'learned'these behaviors from other relatives, the presence of OCDacross generations alone is not sufficient to unequivocallyprove inheritance [47]. However, successive family mem-bers often have different obsessions and compulsions,suggesting that they have not 'learned' them. Whatappears to be inherited is the capacity to respond to com-mon life experiences with obsessions and compulsions.There are also studies of inheritance involving identical(homozygotic) and fraternal (heterozygotic) twins, whichalso provide supportive evidence for an inherited compo-nent in OCD and OCRDs [48].
Molecular genetics studies have begun to provide evi-dence that specific genes may play a role in the manifesta-tions of OCD. Segregation analysis has examined familiarpatterns of OCD transmission [49,50].
The genetic hypothesis suggests at least few major genesimplicated in OCD and OCRDs, thus they are consideredoligogenic disorders. Among others, the following regionshave been suggested as susceptibility loci: 1q, 6q, 9p, 19q,7p and 15q. Specifically, the chromosome 11p15 hasbeen linked and associated with a supposed gender effectin the OCD etiology [51]. Interestingly, deletions andother abnormalities of human chromosome 15q11-q13are associated with two developmental disorders, PWSand Angelman syndrome (AS), which may also presentwith psychiatric symptoms such as binging and otherICD-related and OCRD-related manifestations [52,53].Detailed analysis of the 15q11-q14 sequence correctederrors and gaps in the public access sequence to fullyreveal large segmental duplications at breakpoints forPWS, AS, and inv dup(15) syndromes, confirming thetight correlations between those conditions [54].
Dhossche et al. suggested an association between autism,PWS, AS, catatonia and GABA dysfunction, and thisappears to be particularly interesting considering the clin-ical and partial phenomenic overlap between those condi-tions, which indeed may appear with OCD and OCRD-related symptoms too [55]. PWS may present with atypi-cal psychotic features and motor dysfunctions character-ized by ritualistic, stereotyped and compulsive behaviors,which may be treated with GABA mimetic compoundssuch as lorazepam, valproic acid and possibly topiramate[56]. Many of the known genetically-based neurodevelop-mental disorders are associated with distinctive behaviorphenotypes such as this; behavioral phenotypes havebeen elucidated by clinical research, from distinctive pro-file or social traits, or have emerged as prominent syndro-mic features. Social phenotypic findings exist for fragile X
syndrome, Down syndrome and PWS, Smith-Magenissyndrome, Turner syndrome, Williams syndrome andvelocardiofacial syndrome, all possibly associated withautism [57].
OCD candidate genes have been studied based on theirfunction and also their position in the genome. Serot-onin-related genes in OCD include those coding for the 5-HT transporter (5-HTT) and receptors (5-HT2A, 5-HT2B, 5-HT2C and 5-HT1B) as well the 5-HT enzyme tryptophanhydroxylase [58].
DA-related genes supposed to be implicated in OCDinclude DA transporter (DAT) genes and the D2, D3 and D4receptors [59,60], as well as the catechol-O-methyltrans-ferase (COMT) and monoamine oxidase A (MAO-A)enzymes [61]. Glutamate-related genes (GRIK andGRIN2B) and transporters (SLC1A1) have also been inves-tigated in OCD along with the neurotrophic tyrosinekinase type 3 (NTRK3) and other genes such as the whitematter genes OLIG2 and MOG [62].
However, given the complexity of OCD phenotype, it isunlikely that a single candidate gene will have a majorimpact on the disorder. Additionally, many individualssuffering from OCD have no family members presentingobsessive-compulsive symptoms.
Treatment and managementThe past 20 years have seen the emergency and evaluationof two major effective forms of treatment for OCD andOCRDs: CBT and drug therapy. Additionally, many othermodalities, including physical treatments as electrocon-vulsive therapy (ECT) and ablative neurosurgical proce-dures have been proposed as well and should not betdisregarded even today [63].
Drug treatment using medications with marked effect onserotonergic neurotransmission has been shown to beeffective in decreasing both obsessions and compulsions,while combining this pharmacological approach withCBT has been reported as the most effective strategy formost OCD and OCRDs cases [64].
Yet, regardless the adopted therapeutic strategy, resultsvary depending on many factors including the age ofonset of the disorder, how long it has been left untreated,the OCRD subtype and/or comorbidity, the patient'sinsight and compliance and others [8]. Additionally, thetherapeutic strategy should be 'tailored' for each singlecase.
CBT helps patients learn how to quell the discomfort aris-ing from obsessions and how to reduce or eliminate com-
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pulsive rituals and it includes exposure and responseprevention (ERP) and also cognitive therapy (CT).
Behavior therapy is not something done to a patient: it isa structured set of techniques the patient learns to employwhenever anxiety, discomfort, or dysfunction arisebecause of obsessions or rituals. Basically, patients areasked to find and face the things they fear ('exposure') andthen to refrain from carrying out compulsive rituals ('ritu-als or response prevention'), but other techniques may beemployed as well [65]. Various degrees of success ratio forCBT as OCD or OCRD monotherapy have been reporteddepending on many factors: the source and method of thestudy, the session frequency, the OCRD subtype and oth-ers [10,66]. Also, CBT has been hypothesized to be associ-ated with brain glucose metabolism improvements forOCD patients [67].
Since the combination of CBT and SRI drugs seems toachieve the best results in clinical settings, this has beenproposed as first-line approach in most of cases [64].
Effective SRI treatments for OCD include SSRIs and tricy-clic antidepressants (TCAs), especially clomipramine, atertiary amine. Relatively weak serotonergic TCAs, such asthe predominantly norepinephrergic secondary amines,do not tend to be as effective in OCD and OCRD treat-ment [64]. SRIs also include the serotonergic-norepine-phrergic reuptake inhibitors (SNRIs), the serotoninantagonist-reuptake inhibitors (SARIs) and others, butstronger evidence is needed to support their use as effec-tive monotherapy for OCD and OCRDs or, as for the anti-MAOs, relevant clinical side effects may discourage orlimit their use [68].
The decision to initiate treatment with SSRI alone, CBTonly or a combination, depends on individual patientsvariables. Non-drug compliance, pregnancy, breastfeed-ing, very young or very old or mild OCD patients may pre-fer CBT alone. SSRI treatment should represent thedesirable approach in most of the drug-treated casesbecause of the side effects associated with the TCA clomi-pramine.
Clomipramine still represents an effective treatment forsevere OCD and OCRDs [69], but as the classification ofOCD and OCRDs changed with the past editions of DSMso did the therapeutic approaches.
An ex adiuvantibus confirmation of partial phenomenicoverlap in OCD-related clinical manifestations is histori-cally provided by clomipramine's effectiveness in treatingsuch conditions, also leading researchers focusing on ser-otonergic mechanism [70]. The pharmacological findingthat serotonergic agents are more effective for obsessions
and compulsions rather than non-serotonergic antide-pressants, and that their anti-obsessive benefit it is inde-pendent of the antidepressant action, also contributed tothe separation of OCD from mood disorders [71].
When considering the SSRI class, the choice of a specificdrug depends on evidence-based medicine but also on thepharmacokinetic and pharmacodynamic properties of thebiologically active agent. To mention few, a long-half life(T1/2) should be preferred for very anxious patients,reducing the risk of rebound syndrome (RS) and allowingfewer daily administrations, but it may be not suitable forolder patients. Likewise, pharmacodynamic aspectsshould suggest anticholinergic (anti-Ach), anti-hys-taminic type-1 (Anti-H1) and/or anti-alpha norepinephr-ergic type-1 (anti-α1) side effects to be preferred when ahigher sedation is sought (for example, for very severeICDs, Tourette's and other OCRDs), while the mild pro-DA agonistic action of others (such as the weak one pro-vided by high-dosage sertraline) should be considered forBDD, binging, craving and other OCRD-related pleasure-seeking behaviors.
Indeed the SSRIs are an almost 5-HT 'selective' class ofdrugs: weak pharmacodynamic actions could represent apowerful clinical tool when properly managed.
Because many OCD patients respond to treatment withSRIs, usually requiring and tolerating higher doses com-pared to affective patients, OCD is often deemed a sero-tonergic dysfunctional disorder. However, despite the'selective' efficacy of (S)SRIs, many OCD and OCRDpatients fail to respond ('non-responders') to adequatedoses and time exposures (for example, 20 to 60 mg/dayof paroxetine for 12 weeks or 150 to 300 mg/day of clo-mipramine for 12 weeks), or may require augmentationstrategies, usually performed by employing differentclasses of drugs [64,72]. Additionally, higher doses andthe delay in the onset of action can be accounted for bythe greater delay in downregulation of serotonergic 5-HT1B receptor in the OFC and the subsequent stimulationof 5-HT2A receptor antagonists (such as atypical antipsy-chotics (AA) also known as 5-HT2A>D2 receptor antago-nists) can hasten or augment the effects of SRIs [73].Consequently, the clinical management of resistant OCDand OCRDs may first consider a hyperdose of SRIs, espe-cially for hard-to-treat forms of OCRD (for example,hoarder-collector patients), prior to augmentation strate-gies [74]. The augmentation of SSRIs with clomipramineshowed significant improvements in Y-BOCS scores com-pared to SSRI monotherapy, but pharmacokinetic interac-tions and higher risk for serotonergic malignantsyndrome (SMS) may discourage this kind of procedure[75]. Also, SRI anti-obsessive drugs have occasionallybeen reported to be associated with birth defects, and they
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Drug management of obsessive-compulsive disorder (OCD) and related disorder (OCRD) non-respondersFigure 3Drug management of obsessive-compulsive disorder (OCD) and related disorder (OCRD) non-responders.
Annals of General Psychiatry 2009, 8:13 http://www.annals-general-psychiatry.com/content/8/1/13
should therefore be avoided in pregnant or breastfeedingwomen (while young or old patients may require lowerdoses).
Alternative augmentations for resistant OCD and OCRDcases may include the use of low doses of dopaminergicantagonists (haloperidol and pimozide or other typicalantipsychotics (TA) or the AA class), especially for poor-insight patients (when compliant). AA may also contrib-ute to mood stabilization in drug-induced manic patientsor true bipolars [76]. Also, AAs are less likely to causeextrapyramidal symptoms (EPS) or neuroleptic malignantsyndrome (NMS) in sensitive subjects.
The efficacy of adjunctive TAs or AAs to SRIs in refractoryOCD may be due to direct dopaminergic D2 blockade sep-arate (TA) or together (AA) with 5-HT2 receptor antago-nism. Additionally, SRI-refractory OCD and OCRDspatients may have additional dysfunctional abnormalitiesin dopaminergic pathways that may require augmenta-tion with DA-blocking drugs.
Recent neuroimaging findings have also proposed rilu-zole and other glutamatergic modulators as a possible SRIaugmentation strategy for OCD-refractory patients, butfurther evidence is needed [77-81]. The antiepilepticmood stabilizers such as carbamazepine, topiramate,gabapentin and others, due to the neuroinhibitorial CNSaction of GABA in OCD circuits, norepinephrergic α2 (forexample, clonidine) and β1 blockers (for example, propa-nolol), selective 5-HT1A partial agonists (buspirone), clon-azepam and other benzodiazepines (BDZ), opioid agents(for example, tramadol), antiandrogens and adrenal ster-oids (for example, flutamide), peptides (for example, oxy-tocin), hallucinogenetic agents (for example, lysergic aciddiethylamide (LDS) and other drugs also acting as 5-HT2Apartial antagonists), inositol and more, have been pro-posed, but no univocal opinion on their efficacy for non-responder OCD and OCRDs patients exists (Figure 3).
While a high number of drugs is available for rationalOCD therapy, less literature evidence exists about OCRDnon-responders management, possibly due to a lowerprevalence and clinical recognition of this group; this iswhy a good pharmacological background should never bemissed by the prescriber.
The concept of non-responders also implies a mismatchbetween a diagnostic classification and treatment, andthis may prompt researchers and clinicians to revise cur-rent nosography and biological hypothesis [5,82].
ConclusionA better understanding of the clinical phenomenology,etiology and therapy of obsessive-compulsive-spectrum
disorders will provide clinicians with important informa-tion about the effective management of these conditions.
Most OCDs and OCRDs may go underdiagnosed or maybe not promptly treated. As a consequence, many patientsand their families may suffer unduly, while a delayed ther-apeutic intervention may mean they do not recover aseffectively as an early dagnosis would allow.
Specifically, we suggest the following:
1. An early recognition of OCD and OCRDs will improveoutcome and reduce burden.
2. Following current diagnostic criteria may be a usefulapproach in most cases, but a knowledge of OCD andOCRD phenomenology is a unique opportunity to betteraddress the patient's needs. It also may lead to better com-pliance between the caregiver and the patient through adeeper understanding of each other goals.
3. To date, no univocal opinion exists about the neurobio-logical basis of OCD spectrum disorders. Regardless, it isimportant to know current literature evidence, as this is acore mechanism to proposing a rational therapeutic strat-egy.
4. Spreading knowledge of OCD and OCRD phenomenamay also lead to overcoming the stigma it is associatedwith, and may finally lead to a greater comprehension ofsuch disorders.
Competing interestsThe authors declare that they have no competing interests.
Authors' contributionsMF conceived the study and wrote the main document.FG, CA, SF and SR served in the data and reference collec-tion process. CM, PS and VV contributed in documentreviewing. PF coordinated data collection and helped todraft the manuscript. All authors read and approved thefinal manuscript.
AcknowledgementsThe authors acknowledge Mrs. Rita Santi Amantini for her secretary assist-ance.
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