The term dual diagnosis describes a situation where a person has both a developmental disability and a mental health problem.
The term developmental disability is used when a person has significant limitations in cognitive functioning (intellectual capacity to reason, organize, plan, make judgments and identify consequences) and adaptive functioning (capacity to gain personal independence, based on the person’s ability to learn and apply conceptual, social and practical skills to everyday life).
These limitations originate before the person reaches 18 years of age; are likely lifelong in nature; and affect areas of major life activity such as personal care, language skills and learning abilities.
Developmental disability is an umbrella term for different disabilities. Some are genetic in origin, such as Down syndrome or fragile X syndrome. They can be caused by illness or injury prenatally or during childhood, as is the case with congenital rubella, fetal alcohol syndrome and meningitis. Sometimes the cause is unknown, for example, with autism spectrum disorder.
Because of the overlap between mental health problems and developmental disabilities it's often difficult to tell whether behaviours are related to medical, environmental, emotional or psychiatric issues, or some combination of these factors. There are steps that clinicians can take to better understand how biological, psychological and social factors can affect a person’s mental health.
Many people with developmental disabilities have physical health concerns that can go unnoticed or undertreated. A full physical exam, regular vision and hearing tests, and dental checkups to identify these problems may be required.
The support a person is receiving—or not receiving—influences their behaviour. If they're unable to do the things that are meaningful for them or expected of them, they may become anxious, angry or sad.
There's a difference between having an emotional problem and a psychiatric disorder. We all experience times in our lives when we feel intense negative emotions, such as anger, sadness or anxiety. When repeated efforts to resolve emotional problems fail, the emotional problem can turn into a mental health problem or psychiatric disorder.
There's no clear line that indicates when problems become severe enough to be described as a disorder in people with developmental disabilities. If emotional problems aren't recognized and addressed, they can become more intense and severely affect the person and those around them. Many clinicians use the diagnostic criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) to help screen and assess people for psychiatric disorders.
The relationship between developmental disabilities and mental health problems is complex. Various biological, psychological and social factors make it more likely that a person with a developmental disability will develop a mental health problem.
Some genetic disorders that cause developmental disability can predispose a person to having specific mental health problems. For example, someone who has fragile X syndrome is at increased risk for developing social anxiety, and someone with 22q11 deletion is at increased risk for developing schizophrenia. This is one reason why it's very important to know the cause of a person’s developmental disability.
There is no single, correct intervention for people who have dual diagnosis. Treatment plans should be customized to address each client’s particular needs.
Treatment plans should:
In many cases, treatment includes helping people with employment, housing, finances, leisure activities and basic daily self-care. The professional conducting the assessment may recommend that the person with dual diagnosis see a therapist or start taking medication. Sometimes treatment may include helping families and caregivers adjust support and expectations of the person with a dual diagnosis.
When a person is diagnosed with a psychiatric disorder (e.g., mood disorder, anxiety disorder, schizophrenia, attention-deficit disorder), medication is often one component of the overall treatment plan. It's not always possible to match the symptoms or behaviours of someone with dual diagnosis to a specific psychiatric disorder. Medication may be part of a treatment plan for challenging behaviour when the underlying psychiatric disorder is uncertain or unknown. In these situations, it's very important to know what the medication is targeting, what the behaviour looks like before intervention, and how it changes with medication.
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