Assessment overview

Identification and appropriate treatment of psychiatric disorders can profoundly improve the level of functioning and quality of life in people with developmental disability.

Best practice in psychiatric assessment for people with developmental disability should involve a multidisciplinary team (see Facilitating a multidisciplinary approach to care), and address any modifiable risk factors for psychiatric disorders (see Risk factors for psychiatric disorders in people with developmental disability ). A holistic approach that encompasses the needs of the individual and their support system is vital in accurate psychiatric assessment. Medicare items (eg Team Care Arrangements, Mental Health Treatment Plan) and National Disability Insurance Scheme (NDIS) funding may apply.

Challenges in psychiatric assessment of a person with developmental disability may arise from cognitive and communication deficits, and reduced capacity to tolerate the interview process, examination and investigations.

There can be a tendency for clinicians to underdiagnose psychiatric disorders in the presence of disability. This ‘diagnostic overshadowing’ can be due to overlapping features of developmental disability and the core symptoms of some psychiatric disorders (eg negative symptoms of schizophrenia may be attributed to social difficulties in autism, and compulsive or anxiety disorders may be attributed to obsessionality of autism). Less frequently, overdiagnosis of a psychiatric disorder may occur; for example, challenging behaviour may be attributed to an anxiety or depressive disorder, but at times, may actually reflect a developmental skills deficit (eg language or communication deficit) or presentation of autism spectrum disorder.

Psychiatric assessment of a person with developmental disability should take into consideration:

• the urgency of the presentation and safety of the individual and their carers or support people—for acute situations, see Acute behavioural disturbance
• reasonable adjustments that may facilitate communication and physical examination
• obtaining consent to seek collateral information (see Obtaining collateral information in psychiatric assessment of a person with developmental disability)
• increased emphasis on clinician or carer observations, because people with developmental disability may have difficulty reporting symptoms.

For additional assessment considerations in children and adolescents with developmental disability, see here.