It is common, although erroneous, to think that people with developmental disabilities form a homogeneous group. People with developmental disabilities vary widely on a number of characteristics. It is more accurate to presume that there is as much difference among people with developmental disabilities as there is difference between people with and those without developmental disabilities. In this section, we will discuss some of the similarities and differences -- in age, type of developmental disabilities, living arrangements, level of mental retardation, and level of behavioral problems -- among people with developmental disabilities.

GENDER AND AGE
The majority of clients served by the regional center system are male (56%, see Table 1) and, with the exception of those aged 65 and over, there are more male clients than female clients in each age group. This may reflect the weaker bio-physiology of males (cf., Anastasi, 1972; Gruenberg, 1964; Nance and Engel, 1972); it could also be that, due to differing gender expectations regarding Male and female achievement, developmental disabilities are more readily diagnosed for males than for females (Anastasi, 1972; Richardson, Katz, and Koller, 1986).

Except for the older age groups, there are proportionally more people with developmental disabilities in each age group than is representative of the general population. People aged 0 through 4, for example, represent eight percent of the general population, but slightly over ten percent of people with developmental disabilities are aged 0 through 4. This overrepresentation occurs until the 51 through 64 age group. Twenty-five percent of the general population is aged 51 and over. In contrast, only about six percent of clients with developmental disabilities are aged 51 and over. This probably reflects the lower longevity of people with developmental disabilities. Despite this under-representation of older regional center clients (in comparison with the general population), there has been an increase in the proportion of older regional center clients over time (5.2% versus 5.8% of clients over age 50 in 1984 versus 1989, respectively).

DIAGNOSES
There are four major and distinct types of developmental disability recognized in the Lanterman Act (mental retardation, cerebral palsy, epilepsy, and autism). It is common for a person with developmental disabilities to have two or more developmental disabilities. The presence of two or more developmental disabilities is associated with increased needs for care and supervision. Sixty-one percent of the clients residing in the community have a single diagnosis; 70 percent of the clients residing in a SDC have multiple diagnoses (Table 2).

As noted in Table 2, over one-half (53%) of all clients are diagnosed with "mental retardation only." An additional five percent of clients have been diagnosed with "cerebral palsy only," "epilepsy only," and "autism only." Nearly all of the people with single diagnoses live in the community. It is when a person has two or more developmental disabilities -- thus, when the level of need is higher -- that residence in a SDC is more likely. Indeed, the proportion of clients who reside in a SDC increases as the number of developmental disabilities increases. Thirty-two percent of SDC residents have a multiple diagnosis of mental retardation, epilepsy, and cerebral palsy.

CHARACTERISTICS OF CLIENTS IN SDCs VERSUS CLIENTS IN THE COMMUNITY
Clients who reside in SDCs typically have two or more developmental disabilities. Yet, the majority of clients with two or more developmental disabilities reside in the community. It is the severity level of the developmental disabilities which distinguishes these two groups. As presented in Table 3, nearly three-quarters of all SDC clients are profoundly retarded, need help when toileting, and have major medical problems. By contrast, about 10 percent of clients residing in the community are profoundly retarded or have major medical problems; 39 percent need help when toileting.

Clients residing in SDCs are also more likely to have severe behavior problems, to be frequently violent, to not understand spoken words, to be wheelchair or bedridden, to need to be fed, to have severe loss of sight, or to have severe loss of hearing. Thus, SDC clients differ from community clients in the level of severity of developmental disability, as well as the amount of care and supervision warranted to ensure their health and welfare.

LIVING ARRANGEMENTS
Regional center clients live in a variety of settings (Chart C). The majority (87%) live in settings -- 59 percent live in their own, or familial, home; community care are the residence of an additional 23 percent; and 5 percent of clients are in independent living settings. SDCs provide residence for 8 percent of all clients and of clients reside in health facilities.

As shall be discussed in the following sections, level of mental retardation and level of behavioral problems influence the clients' type of living arrangement.

Level of Mental Retardation and Type of Living Arrangement
More than 90 percent of all regional center clients have a diagnosis of mental retardation (Table 3). People with mental retardation live in a variety of settings in the community (see Table 4). The type of living arrangement varies by the level of mental retardation. Except for those with profound mental retardation, the family home is the most common place of residence across levels of mental retardation. The likelihood of "own home" residence, though, varies somewhat according to level of mental retardation. Over two-thirds of people with mild mental retardation live in their own home; only 20 percent of those with profound mental retardation live in their own home. The likelihood of clients residing in an independent living setting also decreases as the level of mental retardation increases. Ten percent of people with mild mental retardation are in independent living situations. In contrast, fewer than one percent of those with either moderate, severe, or profound mental retardation are in independent living situations.

There also is variability in levels of mental retardation across the several types of out-of-home living arrangements (data not shown in table). Sixty-two percent of community care facility residents have a diagnosis of mild or moderate mental retardation, but only 25 percent of residents in community health facilities and 14 percent of people living in SDCs have a diagnosis of mild or moderate mental retardation. As mentioned before, SDCs primarily serve those with profound mental retardation (71% of the SDC residents). Two-thirds of the residents of health facilities have severe or profound mental retardation.

It is apparent that clients with less severe levels of mental retardation are more likely to reside in settings which are less restrictive (i.e., "own home," "independent living," "community care facilities") than are clients with more severe levels of mental retardation. Clients with profound mental retardation are more likely than those with mild mental retardation to need the intensive services of a SDC or a community health facility. Conversely, clients with mild mental retardation are more likely to be able to live independently.

Behavior and Type of Living Arrangement
Another characteristic on which clients differ is the level of behavioral problems associated a SDC, the developmental disability. As with level of mental retardation and the presence of multiple diagnoses, clients' living arrangements differ depending on the level of behavioral problems.

Clients are more likely to be found in settings with higher levels of direct care and supervision as the level of behavioral problems increases from "no problems" to "severe problems" (Table 5). Seventy-four percent of clients with "no problems," for example, reside in their own home or in independent living settings. As the level of severity of behavioral problems increases, the proportion of clients residing in these settings decreases. A little over one-half (54%) of clients with minimal behavioral problems reside in their own home or are living independently. Two-fifths (42%) of clients with moderate behavioral problems live in similar settings. At the highest level of behavioral problems ("severe problems"), approximately 28 percent of clients reside in either their own home or in independent living settings.

As the level of behavioral problems increases, it is more likely that clients will reside in a developmental center. Although only four percent of clients with "no problems" reside in a SDC, more than one-third of clients with "severe problems" are SDC residents.

Although there is a correlation between level of behavioral problems and type of living arrangements, the correlation is not perfect. Community care facilities, for example, provide residence to clients with "no problems" as well as clients with "severe problems." The majority of clients residing in community health facilities have "no problems," but clients with "minimal," "moderate," and "severe," problems also reside in these facilities. The reason for this variation lies in the great diversity of facilities. For example CCFs designated as ARM Level 2 facilities do not serve clients with severe behavior problems, whereas ARM Level 4 facilities often specialize in serving such clients. In summary, a facility's willingness to accept clients with behavioral problems varies with the type and severity of the problem, the presence of staff qualified to work with clients with behavioral problems, and the nature of the clients' other needs.

The notion of homogeneity among clients with developmental disabilities is belied by this brief overview of client characteristics. Not only is there variability by age and gender, there are differences in the types of diagnoses and living arrangements. There are similarities among clients; for example, change in the level of severity of mental retardation or behavioral problems is associated with change in the most common type of living arrangement. The range of difference and similarity among characteristics of clients with developmental disabilities underscores the necessity of developing a system of service provision which is responsive to complex needs. The following chapters present the State of California's long range plans for shaping and providing care and services for people with developmental disabilities.