Table 4.
Diagnostic concordance of best subset of ACDS items with DSM-IV/ACDS narrowly-defined and broadly-defined diagnoses of adult ADHD using several different scoring rules (n = 345)1
| Prevalence |
Concordance |
|||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scoring rules (number of items endorsed) 2 |
DSM-IV/ACDS ADHD |
Positive on the dichotomized prediction scale |
χ2 | SEN3 | SPEC3 | PPV3 | NPV3 | Κ3 | AUC3 | |||||||
| % | (SD) | % | (SD) | Est | (SD) | Est | (SD) | Est | (SD) | Est | (SD) | Est | (SD) | |||
| I. Four-item scales | ||||||||||||||||
| A. Narrowly-defined | ||||||||||||||||
| 1–4 | 3.6 | (18.6) | 24.2 | (42.8) | 70.0* | 99.6 | (6.3) | 78.6 | (41.0) | 14.9 | (35.6) | 100.0 | (0.0) | .21 | (0.4) | .89 |
| 2–4 | 3.6 | (18.6) | 12.0 | (32.5) | 27.6* | 96.2 | (19.1) | 91.2 | (28.3) | 29 | (45.4) | 99.8 | (4.5) | .41 | (0.5) | .94 |
| 3–4 | 3.6 | (18.6) | 4.4 | (20.5) | 1.2 | 88.1 | (32.4) | 98.7 | (11.3) | 72.6 | (44.6) | 99.5 | (7.1) | .79 | (0.4) | .93 |
| 4 | 3.6 | (18.6) | 3.0 | (17.1) | 0.8 | 66.0 | (47.4) | 99.4 | (7.7) | 80.8 | (39.4) | 98.7 | (11.3) | .72 | (0.4) | .83 |
| B. Broadly-defined | ||||||||||||||||
| 1–4 | 7.7 | (26.7) | 19.8 | (39.8) | 41.1* | 99.8 | (4.5) | 86.8 | (33.8) | 38.8 | (48.7) | 100.0 | (0.0) | .50 | (0.5) | .93 |
| 2–4 | 7.7 | (26.7) | 8.8 | (28.3) | 2.6 | 96.7 | (17.9) | 98.5 | (12.2) | 84.5 | (36.2) | 99.7 | (5.5) | .89 | (0.3) | .98 |
| 3–4 | 7.7 | (26.7) | 5.4 | (22.6) | 5.9* | 65.6 | (47.5) | 99.6 | (6.3) | 93.2 | (25.2) | 97.2 | (16.5) | .75 | (0.4) | .83 |
| 4 | 7.7 | (26.7) | 0.9 | (9.4) | 22.6* | 10.6 | (30.8) | 99.9 | (3.2) | 90.7 | (29.0) | 93.0 | (25.5) | .18 | (0.4) | .55 |
| II. Executive functioning sub-scales | ||||||||||||||||
| A. Narrowly-defined | ||||||||||||||||
| 1–2 | 3.6 | (18.6) | 15.6 | (36.3) | 38.4* | 89.4 | (30.8) | 87.1 | (33.5) | 20.7 | (40.5) | 99.5 | (7.1) | .30 | (0.5) | .88 |
| 2 | 3.6 | (18.6) | 3.2 | (17.6) | 0.3 | 66.9 | (47.1) | 99.2 | (8.9) | 75.8 | (42.8) | 98.8 | (10.9) | .70 | (0.5) | .83 |
| B. Broadly-defined | ||||||||||||||||
| 1–3 | 7.7 | (26.7) | 14.4 | (35.1) | 21.7* | 98.0 | (14.0) | 92.6 | (26.2) | 52.6 | (49.9) | 99.8 | (4.5) | .65 | (0.5) | .95 |
| 2–3 | 7.7 | (26.7) | 7.6 | (26.5) | 0.0 | 87.0 | (33.6) | 99.0 | (9.9) | 88.3 | (32.1) | 98.9 | (10.4) | .87 | (0.3) | .93 |
| 3 | 7.7 | (26.7) | 0.9 | (9.4) | 22.5* | 11.0 | (31.3) | 99.9 | (3.2) | 91.0 | (28.6) | 93.1 | (25.3) | .18 | (0.4) | .55 |
The prevalence estimate based on the scoring rule applied to the subset of items differs significantly from the DSM-IV/ACDS prevalence estimate at .05 level using a two-sided test
As screened positive cases and sub-threshold cases were over-sampled from a larger initial sample in selecting respondents to be administered the clinical follow-up interview, the data for all 345 respondents were weighted to adjust for the over-sampling. The percentages reported in this table are based on analysis of these weighted data.
The scoring rules all use unweighted counts of symptoms endorsed to define predicted cases. The entries in this column are for the number of symptoms required to define a predicted case. The four-item scales in Part I of the table have different items for narrowly-defined and broadly-defined ADHD. The items for narrowly-defined ADHD include difficulty prioritizing work, trouble planning ahead, difficulty sustaining attention, and cannot work unless a deadline. The items for broadly-defined ADHD include difficulty prioritizing work, cannot complete work in allotted time, makes careless mistakes, and difficulty sustaining attention. The executive functioning sub-scales in Part II of the table delete the inattention items from the Part I scales (difficulty sustaining attention in the scales for both narrowly-defined and broadly-defined cases and cannot work unless a deadline in the scale for narrowly-defined cases), resulting in only 2 items in the narrowly-defined and 3 in the broadly-defined sub-scales.
SEN: sensitivity; SPEC: specificity; PPV: positive predictive value; NPV: negative predictive value; Κ: Cohen’s Κ; AUC: area under the receiver operating characteristic curve.