3.3 T HE DEVELOPMENTAL COURSE OF ADHD
3.3.4 Adult outcome
past eight years (65, 59, and 40 months respectively) (Barkley, Fischer et al., 1990).
This pattern is similar to that found in Barkley’s study of clinic-referred ADHD teens (Barkley, Anastopoulos et al., 1991) and Lambert’s follow-up study of 58 hyperactives and controls (Lambert et al. 1987).
With regard to automobile accidents, a later study by Barkley and colleagues (Barkley, Guevremont, Anastopoulos, DuPaul & Shelton, 1993) confirms prior research (Weiss & Hechtman, 1993) that suggested that hyperactive adolescents have a higher incidence of automobile accidents than do normal adolescents.
Barkley’s study followed ADHD teens prospectively for three to five years and found that they were significantly likely to have had more crashes, to have more bodily injuries associated with such accidents, and to be at fault more often for such accidents. They were also more likely to receive traffic citations, particularly for speeding.
Mannuzza et al., 1993). However, in both the Canadian study of Weiss and Hechtman (1993) and the Milwaukee follow-up study of Fischer (1997), the rates of specific forms of substance abuse or dependence were not found to be significantly higher than those found in the control groups.
The Milwaukee follow-up study (Fischer, 1997) documented a significantly higher rate of Major Depression among the hyperactive subjects in young adulthood compared to the control subjects (28% versus 12%). This has not been documented in the other follow-up studies that employed DSM criteria for assessing psychiatric disorders at adult outcome (Mannuzza et al., 1993).
Some research shows that approximately 79% of ADHD children, as adults, complain of difficulties with neurotic symptoms, such as anxiety, sadness, somatic complaints, or other internalising features, and 75% report interpersonal problems versus about 51% and 54%, respectively, of control subjects (Weiss & Hechtman, 1993). The incidence of psychotic disorders in ADHD children at adulthood is no greater than that for the normal control group. The results of the Weiss and Hechtman (1993) study suggest that almost 10% will have attempted suicide within the past three years and about 5% will die from either suicide or accidental injury. Both percentages are considerably greater than those seen in control groups.
With regard to antisocial activities, as adults, individuals with a prior history of ADHD were found to have a greater likelihood of contact with the police and courts, primarily for traffic offences (18% versus 5% for controls) (Weiss & Hechtman, 1993).
However, problems with theft and non-prescription sale of drugs may occur in a significant minority of subjects. In the Canadian follow-up study, approximately 20%
of ADHD children committed acts of physical aggression toward others in adulthood within the past three years, compared to 5% of control children (Weiss & Hechtman, 1993). In the Milwaukee young adult follow-up study, several forms of antisocial activity were more common among the hyperactive than the control subjects: theft of property (85% versus 66%), breaking and entering (20% versus 8%), disorderly conduct (68% versus 54%), assault with fists (74% versus 53%), carrying a weapon (39% versus 11%), assault with a weapon (22% versus 7%), intentionally setting fires (16% versus 5%), and running away from home as a teenager (31% versus 16%) (Fischer, 1997). Overall, 22% of the formerly hyperactive subjects had been arrested for a felony compared to only 3% of the control group. Satterfield, Satterfield and Cantwell (1981) found that between 36% and 52% of their hyperactive subjects had
been arrested at least once. Similarly, Mannuzza, Gittelman, Konig and Giampino (1989) found that 39% of their hyperactive subjects had been arrested (versus 20%
of the control group) and 23% had been arrested more than once (versus 8% of the control group). Consequently, rates of incarceration were also higher in the hyperactive group (9% versus 1%). Only the Weiss and Hechtman (1993) study did not find higher rates of arrest among the sample of Canadian hyperactive children followed into adulthood. It is fair to say that the vast majority of ADHD individuals are not antisocial in adulthood, but that a small number, perhaps 25%, are so and display a persistent pattern of such conduct over time. Klein and Mannuzza (1991) found in their study that the greater arrest and incarceration rates were exclusively among those hyperactive subjects who had Antisocial Personality Disorder in adulthood.
With regard to academic attainment, the trends toward lower academic achievement and ability and greater grade retentions, suspensions, and expulsions evident in the adolescent years increase such that by adulthood, the percentage of ADHD children having difficulties in these areas is even greater than those percentages noted in adolescence and, of course, greater than those of control groups. The Milwaukee study found that by 19-27 years of age, more than 60% of ADHD subjects reported having been suspended from school (versus 18% of the control group) and more than 13% had been expelled (versus 5% of the control group). Although many ADHD children who are now adults will be employed and self-supporting, their general level of educational attainment and socio-economic status is less than that of control children or even their siblings (Mannuzza et al., 1993). Up to 30% will drop out of and never complete high school as compared to less than 10% of control children (Weiss
& Hechtman, 1993). In the Milwaukee follow-up study, the rate of failure to graduate from high school was 32%. Inspection of high school transcripts obtained from these subjects indicated a significantly lower high school grade point average, and their average class ranking in high school was significantly lower. In the Canadian follow- up study, approximately 20% attempted a college programme, yet only 5%
completed a university degree programme as compared to over 41% of control children (Weiss & Hechtman, 1993).
With regard to employment functioning, results from past studies suggest that as adolescents, ADHD individuals are no different in their functioning in their jobs than are normal adolescents (Weiss & Hechtman, 1993). However, these findings need to be qualified by the fact that most jobs taken by adolescents are unskilled or only semi-skilled and are usually part time. As ADHD children enter adulthood and take
on full-time jobs that require skilled labour, independence of supervision, acceptance of responsibility, and periodic training in new knowledge or skills, their deficits in attention, impulse control, and regulating activity level, as well as their poor organizational and self-control skills, could begin to handicap them on the job. The findings from the few outcome studies that have examined job functioning suggest this may be the case. Although ADHD adults are likely to be employed full time, are completely self-sufficient of their families, and are upwardly mobile (increasing in economic status with time), the quality of their work adjustment differs significantly from that of normal control subjects in adulthood (Weiss & Hechtman, 1993). The Milwaukee follow-up study obtained employer ratings of work performance at the young adult assessment and found that hyperactive subjects are rated as performing significantly more poorly at work than are control subjects. ADHD adults are likely to have lower socio-economic statuses than their brothers or control subjects in these studies and to move and change jobs more often, but also to have more part-time jobs outside their full-time employment. Employers have been found to rate ADHD adults as less adequate in fulfilling work demands, less likely to be working independently and to complete tasks, and less likely to be getting along well with supervisors. They also do more poorly at job interviews than do normal individuals.
ADHD adults report that they are more likely to find certain tasks at work too difficult for them. Finally, ADHD adults appear to have a poorer work record and lower job status than normal adults (Weiss & Hechtman, 1993).
Weiss and Hechtman (1993) are the only investigators to date to have studied the social skills of ADHD adults followed prospectively from childhood. Their findings indicate greater social skills and interaction problems for ADHD adults, particularly in the areas of hetero-social skills (male-female interactions) and assertion.
With regard to sexual activity, the Canadian follow-up study (Weiss & Hechtman, 1993) found that sexual adjustment problems were described by as many as 20% of the ADHD group in adulthood, a figure greater than that of the control group (2.4%).
The Milwaukee follow-up study questioned subjects about their sexual activities as part of the evaluation at the young adult follow-up point. Preliminary results indicate that the hyperactive subjects began having sexual intercourse at an earlier age that the control group (15 versus 16 years), have had more sexual partners in their lives (19 versus 7), are more likely to have conceived a pregnancy (38% versus 4%), are less likely to employ birth control methods, are more likely to have contracted a sexually transmitted disease (17% versus 4%), and are more likely to have been
tested for HIV/AIDS (54% versus 21%). Such findings indicate a high-risk sexual lifestyle among the formerly hyperactive subjects on reaching early adulthood, in comparison to the control subjects.
With regard to driving, the study by Weiss and Hechtman (1993) found that significantly more of their hyperactive subjects as adults had been involved in motor vehicle crashes and had received speeding tickets compared to their control groups.
The Milwaukee outcome study did not find a greater number of accidents or speeding tickets by self-report of the subjects at their young adult assessment. However, more hyperactive subjects than control subjects reported having had their licences suspended or revoked (42% versus 28%), having been involved in accidents in which the vehicle was totalled (49% versus 16%), and having been involved in a hit-and-run accident (14% versus 2%). Also, the number of total traffic citations and licence suspensions/revocations was significantly greater in the hyperactive subjects, as was the amount of damage done in their first vehicular crashes. During a behind-the- wheel driving evaluation, the hyperactive subjects were rated by a driving examiner as significantly more distractible and impulsive, and were rated by themselves and their parents as using significantly poorer driving skills.
This chapter has reviewed the literature and existing research regarding the incidence and developmental course of attention deficit hyperactivity disorder. The following chapter will examine the effects of ADHD on the family and will discuss treatment options for ADHD.