The topic of dual diagnosis continues to elicit increased interest of academics and practitioners as they come to terms with the fact that a broad range of abnormal behaviors are often related to developmental disabilities (Davis et al, 2008). This topic has traditionally focused on individuals who experience alcohol/drug related problems with corresponding emotional/psychiatric problems (Mental Health America, 2012), but the scope has expanded to include individuals presenting with two or more behavioral, developmental and mental disorders (Ryan et al, 2010). The aim of this paper is to describe recent research findings on the presentation of abnormal behaviors in persons with known developmental disabilities. In particular, the description will focus on the relationship between anxiety-related behavioral disorders and a number of developmental disabilities, including autism, schizophrenia and intellectual disability.
In their study titled “Anxiety Disorders in Persons with Developmental Disabilities”, Davis et al (2008) note that “…patients with mental retardation, autism, and other pervasive developmental disorders may exhibit comorbid anxiety disorders, such as generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), phobias, and other anxiety symptoms at much higher rates than in the general population” (p. 249). However, these authors observe that the detection of these comorbid anxiety disorders is made more difficult by the presence of the developmental disability as well as other concurrent difficulties, such as communication and behavior challenges, unavailability of standardized assessments specific to diagnosing individuals with developmental disabilities and resulting psychiatric comorbidities, and the unavailability of superior collateral sources of evaluation information.
A strand of emerging literature demonstrates that a variety of abnormal behaviors exhibited by individuals in their various phases of development, such as anxiety disorders, listening difficulties and challenges in comprehending a procedural discourse task, are also frequently comorbid with notorious developmental disorders, including schizophrenia, autistic disorder and Asperger’s disorder (Ryan et al, 2010; Davis et al, 2008). Citing recent research studies, Davies et al (2008) argue that “…adults with autism have almost three times the rate of reported anxiety symptoms, including, panic, agoraphobia, separation anxiety, and generalized anxiety as adults with [developmental disorders] and anxiety was correlated with level of stress” (p. 250). Other reviews, as suggested by these authors, have noted an increased prevalence of anxiety disorders in individuals presenting with known developmental disabilities, such as post-traumatic stress disorder and social anxiety disorder.
Although the above description leaves no doubt that a multiplicity of abnormal behaviors exhibited by individuals are often connected with developmental disabilities, research is still inconclusive on which of the two conditions precedes the other (Lecavalier, 2011). Traditionally, when dual diagnosis was sorely viewed under the lens of alcohol/drug related problems in relationship to the presenting emotional/psychiatric problems, it was generally felt that the emotional/psychiatric problem developed first, forcing the individual to be addicted to drug or alcohol in an attempt to calm the situation down (Mental Health America, 2012). Although this assertion formed a background in understanding alcoholism/drug abuse and related psychiatric problems, it becomes difficult to distinguish the antecedents of various developmental disorders, basically from assessing underlying behavioral orientations and vise versa (Hoevenaars-Van den Boom et al, 2009).
To underline the challenges faced by professionals in establishing the syndrome or disorder which precedes the other, either behavioral or developmental, Langdon et al (2011) underline the need for proper assessment of all the variables at play if proper intervention strategies are to be developed and implemented. For instance, it is a well known fact that psychiatrists often associate deaf/blindness behavior with autism developmental disorder due to the fact that “…the prevalence of autism seems to be positively correlated to hearing impairments, visual impairments and intellectual disabilities” (Hoevenaars-Van den Boom et al, 2009, p. 548). Consequently, it is expected that individuals exhibiting congenital deafblindness posses a higher probability of developing autism than normal individuals. However, the research is yet to be conclusive on whether it is the congenital deaf or blindness that triggers autistic disorder or the blindness is a direct consequence of the developmental disorders. This dearth in knowledge has not only contributed to over-diagnosis of various developmental disorders in individuals exhibiting impaired behavioral orientations (Langdon et al, 2011), but has also complicated the treatment options and interventions available for such individuals (Lecavalier, 2006). Hoevenaars-Van den Boom (2009) provides an example by stating that there exists an over-diagnosis of autistic disorder in individuals “…with sensory impairments because of topographical similarities in behaviors but differences in the underlying mechanisms or processes that cause these behaviors” (pp. 548-549). Such challenges underline the complexity involved in dealing with dual conditions.
In their study titled “Moral Reasoning Theory and Illegal Behavior by Adults with Intellectual disabilities”, Langdon et al (2011) noted that there exists a strong correlation between the concept of moral reasoning and the exhibition of illegal behavior, including crimes, abnormal and antisocial behaviors amongst adolescent offenders. One particular finding that inarguably bears immense weight on the direction of dual diagnosis is that some individuals with noted intellectual disabilities may actually be less likely to exhibit abnormal and/or illegal behaviors than their counterparts in the general population because of the fact that the relationship between engaging in moral reasoning and the exhibition of such behavioral patterns is moderated by intelligence (Langdon et al, 2011). This, therefore, implies that developmental delays in cognitive and moral reasoning coupled with deficits in social skills demonstrated by individuals with known developmental disabilities such as autistic disorder may not necessary be the root cause of the given abnormal behaviors. It, therefore, follows that the level of intelligence in an individual suffering from a developmental disorder may be instrumental in deciding if this particular individual demonstrates abnormal behavior patterns (Langdon et al, 2011). However, research studies that have sorely relied on this perspective to explain dual diagnosis are largely anecdotal (Lecavalier, 2006), thus there is a need to undertake more studies.
Available literature on the relationship between abnormal behaviors and developmental disabilities is wide and varied. In his study titled “Behavioral and Emotional Problems in Young People with Pervasive Developmental Disorders”, Lecavalier (2006) notes that “…behavior problems such as temper tantrums, overactivity, aggression, and self-injurious behaviors are part of the clinical descriptions of autism in current psychiatric diagnostic systems” (p. 1101). This statement implies that it is indeed true that some particular behaviors deemed as abnormal are positively correlated with the presentation or prevalence of developmental disorders. To stress the point, this author argues that there exists an ample evidence to demonstrate that adolescents with pervasive developmental disorders (PDDs) are also known to exhibit a broad array of behavior and emotional challenges, “…with symptoms of anxiety, depression, and attention deficit hyperactivity disorder (ADHD) being the most frequently reported” (p. 1101). Consequently, treatment and intervention measures need to be aimed at not only the noted developmental disorder but also the symptoms exhibiting due to the underlying behavioral orientations (Hoevenaars-Van den Boom et al, 2009; Mental Health America, 2012).
A major point to note in this evaluation is the fact that many known psychiatric disorders, such as anxiety, anxiety deficit disorder, separation anxiety and generalized anxiety, may indeed be under-diagnosed in persons presenting with developmental disabilities because the presence of anxiety is more often likely to be eclipsed by the presence of the developmental disability (Davies et al, 2008). This problem is further exacerbated by the fact that it is often difficult to obtain valid diagnostic information on the persons presenting with the dual conditions (Ryan et al, 2010). It, therefore, becomes difficult to treat these people in the absence of the modified diagnostic criteria as individuals presenting with these developmental disabilities will often experience challenges in attempting to describe the “…internalizing symptoms of anxiety because of deficits in communication, social skills, and intellectual functioning” (Davies et al, 2008, p. 249). Consequently, practitioners must adopt a holistic approach in the treatment of various developmental disorders, which put into consideration the proper management of the disorder as well as the adoption of psychiatric interventions aimed at modifying behavior (Lecavalier, 2006).
To conclude, it is plausible to note that this description of research findings on the relationship between abnormal behaviors and developmental disabilities has illuminated invaluable insights into the broad topic of dual diagnosis. In particular, this description has not only dealt with establishing the relationships between the two conditions as they affect individuals at higher risk, but has also highlighted the best practices that could be used by psychiatrists and other professionals to avail adequate treatment and intervention measures to patients.
Davis, E., Saeed, S.A., & Antonacci, D.J. (2008). Anxiety disorders in persons with developmental disabilities: Empirically informed diagnosis and treatment. Psychiatric Quarterly, 79(3), 249-263.
Hoevenaars-Van den Boom, M.A.A., Antonissen, A.C.F.M., Knoors, H. & Vervloed, M.P.J. (2009). Differentiating characteristics of deafblindness and autism in people with congenital deafblindness and profound intellectual disability. Journal of Intellectual Disability Research, 53(6), 548-558.
Langdon, P.E., Clare, Isabel C.H. & Murphy, G.H. (2011). Moral reasoning theory and illegal behavior by adults with intellectual disabilities. Psychology, Crime & Law, 17(2), 101-115.
Lecavalier, L. (2006). Behavioral and emotional problems in young people with pervasive developmental disorders: Relative prevalence, effects of subject characteristics, and empirical classification. Journal of Autism & Developmental Disorders, 36(8), 1101-1114.
Mental Health America. (2012). Dual diagnosis. Web.
Ryan, J., Woodyatt, G. & Copeland, D. (2010). Procedural discourse in intellectual disability and dual diagnosis. Journal of Intellectual Disability Research, 54(1), 70-80.