Epidemiological data are limited, but<unk>  appears to be very uncommon. The prevalence of<unk>  is unclear but it is probably quite rare, other than in populations of children being reared in the most extreme, deprived settings such as some orphanages. There is little systematically gathered epidemiologic information on<unk> . A cohort study of 211 Copenhagen children to the age of 18 months found a prevalence of 0.9%.<unk>  disorders tend to occur in a definable set of contexts such as within some types of institutions, in the presence of repeated changes of primary caregiver or of extremely neglectful identifiable primary caregivers who show persistent disregard for the child's basic<unk>  needs, but not all children raised in these conditions develop an<unk>  disorder. Studies undertaken on children from Eastern European orphanages from the mid-1990s showed significantly higher levels of both forms of<unk>  and of insecure patterns of<unk>  in the institutionalized children, regardless of how long they had been there. It would appear that children in institutions like these are unable to form selective<unk> s to their caregivers. The difference between the institutionalized children and the control group had lessened in the follow-up study three years later, although the institutionalized children continued to show significantly higher levels of indiscriminate friendliness. However, even among children raised in the most deprived institutional conditions the majority did not show symptoms of this disorder. A 2002 study of children in residential nurseries in Bucharest, in which the DAI was used, challenged the current DSM and ICD conceptualizations of disordered<unk>  and showed that inhibited and disinhibited disorders could coexist in the same child. There are two studies on the incidence of<unk>  relating to high risk and maltreated children in the U.S. Both used ICD, DSM and the DAI. The first, in 2004, reported that children from the maltreatment sample were significantly more likely to meet criteria for one or more<unk>  disorders than children from the other groups, however this was mainly the proposed new classification of disrupted<unk>  disorder rather than the DSM or ICD classified<unk>  or DAD. The second study, also in 2004, attempted to ascertain the prevalence of<unk>  and whether it could be reliably identified in maltreated rather than neglected toddlers. Of the 94 maltreated toddlers in foster care, 35% were identified as having ICD<unk>  and 22% as having ICD DAD, and 38% fulfilled the DSM criteria for<unk> . This study found that<unk>  could be reliably identified and also that the inhibited and disinhibited forms were not independent. However, there are some methodological concerns with this study. A number of the children identified as fulfilling the criteria for<unk>  did in fact have a preferred<unk>  figure. It has been suggested by some within the field of<unk>  therapy that<unk>  may be quite prevalent because severe child maltreatment, which is known to increase risk for<unk> , is prevalent and because children who are severely abused may exhibit behaviors similar to<unk>  behaviors. The APSAC Taskforce consider this inference to be flawed and questionable. Severely abused children may exhibit similar behaviors to<unk>  behaviors but there are several far more common and demonstrably treatable diagnoses which may better account for these difficulties. Further, many children experience severe maltreatment and do not develop clinical disorders. Resilience is a common and normal human characteristic.<unk>  does not underlie all or even most of the behavioral and emotional problems seen in foster children, adoptive children, or children who are maltreated and rates of child abuse and/or neglect or problem behaviors are not a benchmark for estimates of<unk> . There are few data on comorbid conditions, but there are some conditions that arise in the same circumstances in which<unk>  arises, such as institutionalization or maltreatment. These are principally developmental delays and language disorders associated with neglect. Conduct disorders, oppositional defiant disorder, anxiety disorders, post-traumatic stress disorder and social phobia share many symptoms and are often comorbid with or confused with<unk> .<unk>  disorder behaviors amongst institutionalized children are correlated with attentional and conduct problems and cognitive levels but nonetheless appear to index a distinct set of symptoms and behaviors.
Reactive attachment disorder
Autism
Externalizing disorder
Immature personality disorder
Disinhibited attachment disorder
Internalizing disorder
Spectrum disorder
Haltlose personality disorder