and checking is consequently the better option. this reasoning often occurs in a cyclical manner, and can continue for as long as the affected person needs it to in order to feel safe. in cognitive behavioral therapy (cbt), ocd patients are asked to overcome intrusive thoughts by not indulging in any compulsions. they are taught that rituals keep ocd strong, while not performing them causes ocd to become weaker. this position is supported by the pattern of memory distrust; the more often compulsions are repeated, the more weakened memory trust becomes, and this cycle continues as memory distrust increases compulsion frequency. for body-focused repetitive behaviors (bfrb) such as trichotillomania (hair pulling), skin picking, and onychophagia (nail biting), behavioral interventions such as habit reversal training and decoupling are recommended for the treatment of compulsive behaviors. ocd sometimes manifests without overt compulsions, which may be termed "primarily obsessional ocd." ocd without overt compulsions could, by one estimate, characterize as many as 50–60% of ocd cases. insight and overvalued ideation the diagnostic and statistical manual of mental disorders (dsm-5), identifies a continuum for the level of insight in ocd, ranging from good insight (the least severe) to no insight (the most severe). good or fair insight is characterized by the acknowledgment that obsessive–compulsive beliefs are not or may not be true, while poor insight, in the middle of the continuum, is characterized by the belief that obsessive–compulsive beliefs are probably true. the absence of insight altogether, in which the individual is completely convinced that their beliefs are true, is also identified as a delusional thought pattern, and occurs in about 4% of people with ocd. when cases of ocd with no insight become severe, affected individuals have an unshakable belief in the reality of their delusions, which can make their cases difficult to differentiate from psychotic disorders. some people with ocd exhibit what is known as overvalued ideas, ideas that are abnormal compared to affected individuals' respective cultures, and more treatment-resistant than most negative thoughts and obsessions. after some discussion, it is possible to convince the individual that their fears are unfounded. it may be more difficult to practice exposure and response prevention therapy (erp) on such people, as they may be unwilling to cooperate, at least initially. similar to how insight is identified on a continuum, obsessive-compulsive beliefs are characterized on a spectrum, ranging from obsessive doubt to delusional conviction. in the united states, overvalued ideation (ovi) is considered most akin to poor insight—especially when considering belief strength as one of an idea's key identifiers—but european qualifications have historically been broader. furthermore, severe and frequent overvalued ideas are considered similar to idealized values, which are so rigidly held by, and so important to affected individuals, that they end up becoming a defining identity. in adolescent ocd patients, ovi is considered a severe symptom. historically, ovi has been thought to be linked to poorer treatment outcome in patients with ocd, but it is currently considered a poor indicator of prognosis. the overvalued ideas scale (ovis) has been developed as a reliable quantitative method of measuring levels of ovi in patients with ocd, and research has suggested that overvalued ideas are more stable for those with more extreme ovis scores. cognitive performance though ocd was once believed to be associated with above-average intelligence, this does not appear to necessarily be the case. a 2013 review reported that people with ocd may sometimes have mild but wide-ranging cognitive deficits, most significantly those affecting spatial memory and to a lesser extent with verbal memory, fluency, executive function, and processing speed, while auditory attention was not significantly affected. people with ocd show impairment in formulating an organizational strategy for coding information, set-shifting, and motor and cognitive inhibition. specific subtypes of symptom dimensions in ocd have been associated with specific cognitive deficits. for example, the results of one meta-analysis comparing washing and checking symptoms reported that washers outperformed checkers on eight out of ten cognitive tests. the symptom dimension of contamination and cleaning may be associated with higher scores on tests of inhibition and verbal memory. children approximately 1–2% of children are affected by ocd. obsessive–compulsive disorder symptoms tend to develop more frequently in children 10–14 years of age, with males displaying symptoms at an earlier age, and at a more severe level than females. in children, symptoms can be grouped into at least four types, including sporadic and tic-related ocd. associated conditions people with ocd may be diagnosed with other conditions as well, such as obsessive–compulsive personality disorder, major depressive disorder, bipolar disorder, generalized anxiety disorder, anorexia nervosa, social anxiety disorder, bulimia nervosa, tourette syndrome, transformation obsession, asd, adhd, dermatillomania, body dysmorphic disorder, and trichotillomania. more than 50% of people with ocd experience suicidal tendencies, and 15% have attempted suicide. depression, anxiety, and prior suicide attempts increase the risk of future suicide attempts. it has been found that between 18 and 34% of females are currently experiencing or will experience ocd in their lifetime. of that 18-34%, 7% are likely to have an eating disorder. fewer than 5% of males have ocd and an eating disorder. individuals with ocd have also been found to be affected by delayed sleep phase disorder at a substantially higher rate than the general public. moreover, severe ocd symptoms are consistently associated with greater sleep disturbance. reduced total sleep time and sleep efficiency have been observed in people with ocd, with delayed sleep onset and offset. some research has demonstrated a link between drug addiction and ocd. for example, there is a higher risk of drug addiction among those with any anxiety disorder, likely as a way of coping with the heightened levels of anxiety. however, drug addiction among people with ocd may be a compulsive behavior. depression is also extremely prevalent among people with ocd. one explanation for the high depression rate among ocd populations was posited by mineka, watson, and clark (1998), who explained that people with ocd, or any other anxiety disorder, may feel "out of control". someone exhibiting ocd signs does not necessarily have ocd. behaviors that present as obsessive–compulsive can also be found in a number of other conditions, including obsessive–compulsive personality disorder (ocpd), autism spectrum disorder (asd), or disorders in which perseveration is a possible feature (adhd, ptsd, bodily disorders, or stereotyped behaviors). some cases of ocd present symptoms typically associated with tourette syndrome, such as compulsions that may appear to resemble motor tics; this has been termed tic-related ocd or tourettic ocd. ocd frequently occurs comorbidly with both bipolar disorder and major depressive disorder. between 60 and 80% of those with ocd experience a major depressive episode in their lifetime. comorbidity rates have been reported at between 19 and 90%, as a result of methodological differences. between 9–35% of those with bipolar disorder also have ocd, compared to 1–2% in the general population. about 50% of those with ocd experience cyclothymic traits or hypomanic episodes. ocd is also associated with anxiety disorders. lifetime comorbidity for ocd has been reported at 22% for specific phobia, 18% for social anxiety disorder, 12% for panic disorder, and 30% for generalized anxiety disorder. the comorbidity rate for ocd and adhd has been reported to be as high as 51%. causes main article: cause of obsessive-compulsive disorder the cause of ocd is unknown. both environmental and genetic factors are believed to play a role. risk factors include a history of adverse childhood experiences or other stress-inducing events. drug-induced ocd some medications and other drugs, such as methamphetamine or cocaine, can induce obsessive-compulsive disorder (ocd) in people without previous symptoms. some atypical antipsychotics (second-generation antipsychotics) such as olanzapine (zyprexa) and clozapine (clozaril) can induce ocd in people, particularly individuals with schizophrenia. genetics there appear to be some genetic components of ocd causation, with identical twins more often affected than fraternal twins. furthermore, individuals with ocd are more likely to have first-degree family members exhibiting the same disorders than matched controls. in cases in which ocd develops during childhood, there is a much stronger familial link in the disorder than with cases in which ocd develops later in adulthood. in general, genetic factors account for 45–65% of the variability in ocd symptoms in children diagnosed with the disorder. a 2007 study found evidence supporting the possibility of a heritable risk for ocd. research has found there to be a genetic correlation between anorexia nervosa and ocd, suggesting a strong etiology. first and second hand relatives of probands with ocd have a greater risk of developing anorexia nervosa as genetic relatedness increases. a mutation has been found in the human serotonin transporter gene hsert in unrelated families with ocd. a systematic review found that while neither allele was associated with ocd overall, in caucasians, the l allele was associated with ocd. another meta-analysis observed an increased risk in those with the homozygous s allele, but found the ls genotype to be inversely associated with ocd. a genome-wide association study found ocd to be linked with single-nucleotide polymorphisms (snps) near btbd3, and two snps in dlgap1 in a trio-based analysis, but no snp reached significance when analyzed with case-control data. one meta-analysis found a small but significant association between a polymorphism in slc1a1 and ocd. the relationship between ocd and catechol-o-methyltransferase (comt) has been inconsistent, with one meta-analysis reporting a significant association, albeit only in men, and another meta analysis reporting no association. it has been postulated by evolutionary psychologists that moderate versions of compulsive behavior may have had evolutionary advantages. examples would be moderate constant checking of hygiene, the hearth, or the environment for enemies. similarly, hoarding may have had evolutionary advantages. in this view, ocd may be the extreme statistical tail of such behaviors, possibly the result of a high number of predisposing genes. brain structure and functioning imaging studies have shown differences in the frontal cortex and subcortical structures of the brain in patients with ocd. there appears to be a connection between the ocd symptoms and abnormalities in certain areas of the brain, but such a connection is not clear. some people with ocd have areas of unusually high activity in their brain, or low levels of the chemical serotonin, which is a neurotransmitter that some nerve cells use to communicate with each other, and is thought to be involved in regulating many functions, influencing emotions, mood, memory, and sleep. autoimmune a controversial hypothesis is that some cases of rapid onset of ocd in children and adolescents may be caused by a syndrome connected to group a streptococcal infections (gabhs), known as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (pandas). ocd and tic disorders are hypothesized to arise in a subset of children as a result of a post-streptococcal autoimmune process. the pandas hypothesis is unconfirmed and unsupported by data, and two new categories have been proposed: pans (pediatric acute-onset neuropsychiatric syndrome) and cans (childhood acute neuropsychiatric syndrome). the cans and pans hypotheses include different possible mechanisms underlying acute-onset neuropsychiatric conditions, but do not exclude gabhs infections as a cause in a subset of individuals. pandas, pans, and cans are the focus of clinical and laboratory research, but remain unproven. whether pandas is a distinct entity differing from other cases of tic disorders or ocd is debated. a review of studies examining anti-basal ganglia antibodies in ocd found an increased risk of having anti-basal ganglia antibodies in those with ocd versus the general population. environment ocd may be more common in people who have been bullied, abused, or neglected, and it sometimes starts after a significant life event, such as childbirth or bereavement. it has been reported in some studies that there is a connection between childhood trauma and obsessive-compulsive symptoms. more research is needed to understand this relationship better. mechanisms main article: biology of obsessive–compulsive disorder neuroimaging some parts of the brain showing abnormal activity in ocd functional neuroimaging during symptom provocation has observed abnormal activity in the orbitofrontal cortex (ofc), left dorsolateral prefrontal cortex (dlpfc), right premotor cortex, left superior temporal gyrus, globus pallidus externus, hippocampus, and right uncus. weaker foci of abnormal activity were found in the left caudate, posterior cingulate cortex, and superior parietal lobule. however, an older meta-analysis of functional neuroimaging in ocd reported that the only consistent functional neuroimaging finding was increased activity in the orbital gyrus and head of the