ABSTRACT
During the last years obsessive-compulsive disorder (OCD) has been reported with increased prevalence in pediatric population; this is due to the development of more specific assessment methods. This evolution in the evaluation tools has given rise to the possibility of characterizing OCD presentation in children and adolescents. In childhood, OCD is a chronic and distressing disorder that can lead to severe impairments in social, academic and family functioning. Current diagnosis criteria for pediatric OCD are the same than those used in adults. During all life span, obsessive and compulsive symptoms are necessary to establish the presence of the disorder. There are several different clinical manifestations among age groups, different evolution among children, adolescents and adults; all these represent a diagnostic and therapeutic challenge for the clinician. Several classifications incorporate pediatric OCD, especially those related to the familiar presentation form and patterns of comorbidity, mainly with tics disorders. At least 50% of children and adolescents with Gilles de la Tourette syndrome develop obsessive-compulsive symptoms or OCD in adulthood and almost a half of early-onset OCD subjects have a tics history. These findings support the notion that tics disorders are the comorbidity more closely related with early-onset OCD, giving elements to consider this association as a specific pediatric OCD subtype. In this age group population, comorbidity has been reported as high as in adulthood; some diagnoses are especially prevalent during childhood and others during adolescence. On the whole, anxiety disorders are frequent with OCD, generalized anxiety disorder, panic attack, social phobia and anxiety separation disorder. Comorbidity related with affective disorders is high too. The OCD association with major depressive disorder (MDD) in childhood is low but increases in adolescence; MDD reaches similar adult comorbidity rates in adolescence. Higher comorbidity prevalence of MDD has been found more related to the duration of OCD-illness than early-onset. Bipolar disorder (BD) is another frequent comorbid entity with great clinical relevance. When BD is the main diagnosis, comorbidity with OCD shows a prevalence of 16%; when OCD is the main diagnosis, comorbidity with BD shows a prevalence of 44%, showing an unidirectional relation. Some studies have shown even higher comorbidity prevalence of BD when considering bipolar spectra dimension as hypomania and cyclothymic disorder (30% and 50%, respectively) in OCD samples. Adults with OCD and BD comorbidity have more frequent episodic form, a greater number of concurrent mayor depressive episodes and a higher rate of religious or sexual obsessions. Adults with OCD without BD comorbidity show more rituals and compulsions. A recent study in pediatric population with BD and OCD found that BD type II was the must common related diagnosis, when age was considered, subjects with bipolar disorder resulted to have an earlier onset of OCD. Other comorbid diagnoses frequently reported in this early-onset OCD population are externalizing disorders as attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). Children and adolescents with OCD have high rates of comorbid ADHD; this co-occurrence seems to be bidirectional. There is a consistent preponderance of males in most epidemiological studies. The onset of ADHD preceded the onset of OCD and the onset of OCD was earlier when ADHD was comorbid. Children with OCD plus ADHD compared with peers with OCD without ADHD show higher attentional and social problems, as well as aggressive high scores. ADHD is a risk factor for ODD. A valid and reliable clinical interview is needed to establish differential diagnosis among OCD and other compulsive behaviors and intrusive thoughts present in disorders like anorexia nervosa, body dysmorphic disorder, hypochondrias, tics disorders and impulse control disorders. All these categories have been considered as part of the obsessive-compulsive disorders spectrum. It is important to establish the difference between obsessions with poor insight common in early-onset OCD and overvalued ideas or delusions. Pervasive disorders as autism and Asperger syndrome frequently show stereotyped behaviors which may be considered as obsessive-compulsive symptoms. The diagnostic evaluation of children and adolescents with OCD includes a careful assessment and review of current and past obsessive-compulsive symptoms and comorbid conditions. This evaluation requires interviewing both child/adolescent and parents and usually requires more than one session. For children who do not regard their symptoms as excessive, information from parents, and if possible from teachers, is essential to identify the range of symptoms, severity and context. Many children and adolescents feel confused and embarrassed with their symptoms. It is important to dedicate time to build a true clinical alliance to elicit the story of their symptoms, as well as the impact on a child's thoughts and feelings. There are several useful instruments to establish OCD diagnosis and severity in children and adolescents. Self-report questionnaires have been used to identify the presence and severity of OCD symptoms. The most used self-rated measures for pediatric OCD are the 44-item Leyton Obsession Inventory-Child version (LOI-CV) and its shorter version, the 20-item LOI-CV Survey Form, and the Maudsley Obsession-Compulsion Inventory (MOCI). Clinician-administered interviews may be a more reliable method to identify obsessive-compulsive disorders in youth. The Childs Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) is a commonly used Clinician-Rated measure of OCD symptoms derived from the Adult Yale-Brown Obsessive-Compulsive Scale. CY-BOCS Spanish version was translated in México and as the original version it must be applied to parents and children/adolescents separately; the clinician establishes then the best clinical information with all the data. The initial CY-BOCS section consists of a symptom checklist covering a comprehensive array of obsessions and compulsions. The severity score is derived from the second section of the measure in which global rating of time spent, interference, distress, resistance and control associated with obsessions and compulsions are generated. Separate scores are obtained for obsessions and compulsions, which, when combined, yield a total severity score of a maximum 40 points. Scores greater than or equal to 16 indicate clinically significant OCD in children and adolescents. The knowledge we now have about pediatric OCD pharmacotherapy is better. Several studies have demonstrated the efficacy of clorimipramine. This was the first agent approved for use in pediatric populations with OCD. Subsequent multisite randomized, placebo-controlled trials of selective reuptake inhibitors (SSRIs) have also demonstrated significant efficacy in pediatric population. Almost all meta-analysis with SSRIs studies in children and adolescents with OCD have proved their efficacy. The most common adverse effects of SSRIs are nausea, insomnia, activation and headache. These effects are transient and most children tolerate them. The availability and effectiveness of SSRI have changed dramatically the OCD treatment, and neurobiological and neuroimaging advances have supported their use. Many children and adolescents with OCD need multiple treatments including cognitive behavior therapy (CBT), pharmacologic treatment, parental, family and teachers training. These interventions need to be applied by experts in order to be effective. CBT is a well-documented and effective intervention for adults with OCD. The potential usefulness of CBT for pediatric OCD has been valued and the results report that combined CBT and pharmacotherapy have proved high and sustained response in children and adolescents with OCD.
El trastorno obsesivo-compulsivo (TOC) se ha reportado en los últimos tiempos con mayor prevalencia en la edad pediátrica que lo reportado anteriormente gracias a una mejor caracterización de su presentación en niños y adolescentes y al desarrollo de mejores métodos de evaluación. Por sus características en la infancia el TOC ha dado pauta a diversas clasificaciones, una de estas formas de clasificación está condicionada por la coexistencia o comorbilidad con otros trastornos. Los tics o Trastorno de Gilles de la Tourette están fuertemente relacionados con un inicio temprano y con agregación familiar; la mitad de los niños y adolescentes con síndrome de Gilles de la Tourette desarrollan TOC. El 60% de los niños y los adolescentes que acuden a buscar tratamiento por TOC han tenido historia de trastornos por tics a lo largo de la vida. La comorbilidad del TOC con otros problemas ansiosos durante la infancia y la adolescencia es alta, en especial con el trastorno de ansiedad por separación, la fobia social, el trastorno de ansiedad generalizada y las fobias específicas. El trastorno depresivo mayor (TDM), es frecuentemente comórbido, más en los adolescentes que en los niños, el TDM comórbido se ha vinculado más con la duración del TOC que con la edad de inicio temprano. Con respecto al trastorno bipolar (TB), los reportes también muestran importante relación con el TOC. Las investigaciones de comorbilidad han estudiado el impacto del TB sobre el curso del TOC y encontraron mayor frecuencia de: curso episódico, episodios depresivos, deterioro funcional, hospitalizaciones y uso de polifarmacia. Otras investigaciones sobre esta comorbilidad TB/TOC vs. TOC han reportado mayor frecuencia del diagnóstico de TB tipo II y mayor asociación con inicio temprano del TOC. También se ha reportado frecuentemente la comorbilidad con los trastornos externalizados y particularmente con el trastorno por déficit de atención e hiperactividad (TDAH), que se ha asociado con un inicio más temprano del TOC, disfunción social y académica. Este patrón comórbido TOC/TDAH está vinculado a mayores problemas de inatención y conductas agresivas y se presenta más frecuentemente en hombres. El TDAH es un factor de riesgo para presentar trastorno negativista y desafiante o trastorno disocial en la adolescencia. Otras comorbilidades importantes a considerar son los trastornos del espectro obsesivo-compulsivo como los trastornos del control de los impulsos, trastorno dismórfico corporal y de la conducta alimentaria y trastorno sexual compulsivo. La comorbilidad con trastornos psicóticos como la esquizofrenia debe ser tomada en cuenta. En la evaluación de niños y adolescentes con TOC se requiere una investigación exhaustiva sobre los síntomas obsesivos-compulsivos actuales y pasados, así como su comorbilidad e historia familiar. Las entrevistas con los niños requieren de la participación de los padres y profesores. Muchos niños y adolescentes se sienten avergonzados por sus síntomas por lo que es importante dar tiempo necesario para lograr la confianza del chico para hablar de sus síntomas. Existen diversos instrumentos útiles para establecer la severidad del TOC en niños y adolescentes. Entre los cuestionarios auto-aplicables se encuentra el Inventario de Obsesiones de Leyton (LOI) y el inventario de obsesiones y compulsiones de Maudsley (MOCI). La Escala de Yale-Brown para Niños (CY-BOCS) es de los instrumentos más frecuentemente utilizados en la clínica e investigación, que evalúan los tipos de obsesiones y compulsiones así como su severidad. La mayoría de los niños con TOC requieren múltiples tratamientos, por ejemplo: terapia cognitivo-conductual, fármacos, entrenamiento conductual para los familiares, etc. La disponibilidad de los inhibidores selectivos de la recaptura de serotonina (ISRS) ha cambiado sorprendentemente el tratamiento del TOC con efectividad basada en evidencia. Hasta el momento, se reconoce que la combinación de terapia cognitivo-conductual y tratamiento farmacológico con ISRS es la estrategia con mayores resultados y mejoría sostenida.
ABSTRACT
The obsessive-compulsive disorder (OCD) is being reported now with increased prevalence in pediatric population than in the past, associated with the development of more specific assessment methods. This evolution has opened the possibility to characterize OCD presentation in children and adolescents. OCD in childhood is a chronic and distressing disorder that can lead to severe impairments in social, academic and family functioning. Currently, pediatric OCD criteria are the same than in adults. The presence of obsessive and compulsive symptoms are needed to establish the diagnosis but, because of the lower levels of cognitive awareness in children, they are less likely to consider their OCD symptoms as excessive or unreasonable. The DSM-IV does not require that symptoms be recognized as senseless or unrealistic for the diagnosis to be made in children. Overall, there are several clinical differences in the younger age groups that make this disorder a diagnostic and treatment challenge for clinicians. Epidemiologic studies have been conducted in adolescent population. These studies report a prevalence in the range of 2% to 4% with a slight predominance in males than females. In Mexico, there are no studies in this population to confirm these rates. Frequently children, more than adolescents and adults, may present compulsive behavior without obsessions, which are related to immature cognitive development. The obsessive-compulsive symptoms have differences between age groups (children, adolescents and adults). Children may be somewhat more likely to engage in compulsive reassurance- seeking and involve their parents in their rituals. The most common obsessions in childhood are related to contamination and germs, followed by fears to harm others. The most common compulsions are washing, repeating and checking. Adolescents present more frequently religious and sexual contents in their obsessions, and similar about aggression as children. Related to compulsions, children and adolescents develop hoarding more frequent than adults. Several studies suggest a mean age of childhood OCD from 6 to 11 years of age, but there are two peaks of more frequent cases presentation: in early childhood and early adolescence. Regarding the OCD early-onset, course studies have reported chronicity in most subjects, 50% of them meeting full OCD criteria seven years later. Meta-analytic studies about predictors and persistence of pediatric OCD diagnoses show persistence in 41% of the sample with full OCD and 60% full or sub-threshold OCD. Early beginning of OCD increase duration of illness and is a predicted of major persistence. Comorbid psychiatric illnesses and poor initial treatment response were poor prognostic factors. Regarding symptoms during illness course, the pattern and type frequently shift over time, although the number of symptoms typically remains constant. Pediatric OCD has evoked distinct classifications related to the familiar presentation form and comorbidity, especially with tics disorders. Studies have reported that children with tics disorders show several differences in their reported symptom types when compared with the group with no history of tics, for example, they are more likely to endorse repetition of routine behaviors unrelated to harm avoidance. Contamination and washing rituals are more common in the OCD child without tics. Findings are consistent with several studies in clinical assessed adult samples which have shown that the tic-related OCD can be distinguished as a subtype of OCD. These adults are more likely to report obsessions involving a need of symmetry and compulsions involving touching, starting and counting. There are also evidence that the tic-related OCD may be lees likely to monotherapy with a selective serotonin reuptake inhibitor. Another way to understand this disorder is subtyping symptoms using factorial analysis. Several authors have proposed at least four subtypes or factors (washers, hoarders, checkers and sexual/religions symptoms). Some studies with children and adolescents have shown limitations to conduct a factorial analysis, although some others with better methods have showed similarity between OCD symptoms dimensions structure in children and adults. The etiology of OCD is not clear, but the evidence in familiarity, segregation analysis and twins studies have established the role of genetics in the cause factors and is considered as a complex genetic disorder. Twin studies find a high concordance rate for monozygotic twins (53-87%) and dizygotic twins (22-47%). The prevalence of OCD is higher among first degree relatives of affected subjects, early-onset OCD has a higher rate of first degree relatives with TOC. Association studies with candidate genes have been done in early-onset OCD but significant results have not been replicated.
El trastorno obsesivo compulsivo se ha reportado en los últimos tiempos con mayor prevalencia en la edad pediátrica que lo reportado anteriormente, esto se debe probablemente a una mejor caracterización de su presentación en niños y adolescentes y al desarrollo de mejores métodos de evaluación. Los criterios diagnósticos son los mismos para niños, adolescentes y adultos. Debido a su bajo nivel de conciencia, los niños pueden no considerar sus obsesiones como exageradas o ilógicas por lo que el DSM-IV no incluye este criterio en este grupo de edad. Aunque hay muchas similitudes sintomáticas a distintas edades, también hay importantes diferencias que convierten este padecimiento en un reto diagnóstico y de tratamiento en el TOC de inicio temprano. La prevalencia del TOC pediátrico se ubica en un rango de 2% a 4%, con una predominancia de los hombres en relación a las mujeres. En México aún no se cuenta con estudios que confirmen estas cifras en esta forma de presentación pediátrica. Frecuentemente los niños, más que los adolescentes y los adultos, pueden presentar conductas compulsivas, sin un componente obsesivo, lo cual probablemente se asocie al desarrollo cognitivo. Los síntomas obsesivos y compulsivos presentan diferencias en el contenido de acuerdo al grupo etario. Las obsesiones más comunes en el TOC de inicio temprano son las relacionadas a la contaminación y gérmenes con compulsiones relacionadas a lavado y revisión. Otras obsesiones frecuentes son el temor a dañar a otros. Se ha identificado que los adolescentes presentan con mayor frecuencia obsesiones sexuales o religiosas y, junto con los niños, más obsesiones agresivas y compulsiones de atesoramiento que los adultos. Por sus características el TOC de inicio en la infancia ha dado pauta a diversas clasificaciones, como son la presencia comórbida de tics y la agregación familiar con más de un integrante con el padecimiento. Algunos estudios han reportado diferencias entre los niños que padecen TOC con tics versus aquellos sin tics, como es la mayor frecuencia de rituales de repetición sin contexto de evitación al daño y menor frecuencia de síntomas relacionados con contaminación/lavado. Otra forma de clasificación que en la actualidad ha permitido la subdivisión del TOC en subtipos se ha apoyado en el análisis factorial, donde se han identificado subtipos en adultos y recientemente en niños y adolescentes con consistencia entre autores. Los subtipos propuestos son: lavado/contaminación, simetría/ orden, obsesiones sexuales/religiosas y atesoramiento. Respecto de las hipótesis etiológicas, las evidencias de agregación familiar y los estudios en gemelos han esclarecido el importante papel genético de este trastorno. Otras teorías biológicas no genéticas para el TOC que se han considerado son las lesiones cerebrales focales y secuelas inmunes generadas por infecciones con el estreptrococo beta-hemolítico del grupo A que podrían explicar alguna proporción de los individuos con TOC. Diversas líneas de investigación han evidenciado que la neuropatología del TOC se encuentra en el circuito cortico-estriado-tálamo-cortical, donde están implicadas la disfunción de la dopamina, la serotonina, el glutamato y el GABA. Particularmente existe evidencia sobre la serotonina, dada la amplia utilización y probada efectividad de los inhibidores selectivos de la recaptura de serotonina (ISRS) en el tratamiento del TOC. Los estudios electrofisiológicos y con potenciales relacionados con eventos (PREs) han sido limitados en adultos y no hay reportes en población pediátrica. Por medio de estudios de neuroimagen como la tomografía axial computarizada (TAC), se ha reportado: disminución de volumen bilateral en el núcleo caudado y cambios estructurales en los ganglios basales ante sintomatología obsesivo-compulsiva durante la adolescencia. La tomografía por emisión de positrones (TEP) en adultos ha sugerido un incremento en el metabolismo del giro orbital y la cabeza del núcleo caudado, mientras que en sujetos con una edad de aparición en la adolescencia se ha reportado un incremento en el metabolismo en regiones orbito-frontal izquierda, sensorio-motor derecha, giro del cíngulo anterior y prefrontal bilateral.