Tyrrell J., Dodd P.

Reported: Mental Health, Intellectual Disabilities and the Aging Process, United Kingdom, Blackwell Publishing, 2003, pp22 - 37

Keywords: psychopathology; old age; psychiatric disorders; psychiatric assessment; mental health

In the general population, there is a high prevalence of psychiatric disorder in older people. This is due to the increased prevalence of dementia and the increase in depressive episodes with age. With age in the incidence of organic psychiatric disorders increases, as well as complications from physical illness and sensory impairments. There is a need for a specialisation in the psychiatry of old age to reflect the need for expertise in this area as presentation of psychiatric illness differs in the older person, particularly in older persons with intellectual disabilities (ID). The chapter concentrates on psychopathology of common psychiatric disorders in old age.

The prevalence of psychiatric disorder is higher in people with ID than in the general population. Lund (1985) found a prevalence of 27.1% for psychiatric disorder in a population of 302 adults older than 20 years with ID. In the older age-group 45-64 years (n=67), behaviour disorder was present in 10.4%, psychosis in 1.5% , dementia at 6%, autism at 1.5%, neurosis at 1.5%, depression at 6% and schizophrenia at 3.1%.

Pary (1993) looked at the medical records of 247 inpatients with ID or autism with regard to psychiatric disorder and found that elderly adults (age >55 years) with ID had significantly more medical problems than younger adults (age 18-54 years). Patel et al., (1993) used the Psychological Assessment Schedule for Adults with Developmental Disabilities (PAS-ADD) and DSM-111 criteria to assess 105 people > 50 years and found prevalence of dementia of 11.4%, mood disorder of 6.7%, and generalised and phobic anxiety 5.8%. Sansom et al (1994) used DSM-111-R criteria to examine 124 residents over the age of 60 years and ID. They found a prevalence of dementia of 12.9%, mood disorder 8.9%, and schizophrenia 6.5%.

Cooper (1997a) in Leicestershire, England, found high rates of psychiatric morbidity in 134 adults aged over 65 years. Using the Present Psychiatric State for Adults with Learning Disability (PPS-LD), a semi-structured psychiatric interview, she found that 61.9% had psychiatric morbidity compared to 43.8% in 73 adults under age 65 years. Cherry et al. (1997) compared 168 older adults to 168 young adults with ID for psychopathology using the Diagnostic Assessment of the Severely Handicapped (DASH) (see Matson et al.,1991). Cherry found that behaviour disorders were the most common disorders.




The above studies show that people with ID have a high prevalence of psychiatric disorder that increases with age. Increased frequency of dementia is responsible for a large proportion of psychiatric disorder in later life.