Table 2. Demographic and Diagnostic Characteristics of Each Mental Health Group in the Dunedin Cohort.

Measures	Total N	Full cohort	0 waves (N = 171)	1–2 waves (N = 409)	3 + waves (N = 408)
Note. ADD = attention deficit disorder; PTSD = posttraumatic stress disorder.
a The p-factor, derived from confirmatory factor analysis of symptom-level data collected between ages 18 and 38, represents an individual’s propensity to develop any and all forms of common psychopathologies (Caspi et al., 2014).
		%	%	%	%
Demographic
Sex (% male)	988	51.3	56.7	52.6	47.8
Type of disorder (ages 11–38)
ADD	953	6.2	0	4.7	10.1
Conduct disorder	953	17.6	0	12.2	30.0
Any anxiety	988	57.5	0	53.3	85.8
Depression	988	48.3	0	39.1	77.7
Substance abuse/dependence	988	41.2	0	35.4	64.2
PTSD	983	8.9	0	3.5	17.9
Schizophrenia	953	3.9	0	0	9.3
Mania	947	1.0	0	0	2.3
Age of onset
First diagnosis before age 15	973	34.6	0	24.6	58.8
First diagnosis at age 38	973	2.6	0	6.3	0
		M (SD)	M (SD)	M (SD)	M (SD)
Indicators of mental disorder severity
Comorbidity
Different lifetime diagnoses (mean)	988	1.8 (1.3)	0 (0)	1.5 (0.7)	2.8 (1.0)
Persistence
Waves in which they received a diagnosis	988	2.3 (1.8)	0 (0)	1.5 (0.5)	4.1 (1.0)
Impairment
Rating of functional impairment (max ever)	974	3.7 (1.2)	—	3.5 (1.1)	4.4 (0.8)
Symptom Score
p-factor (z score)a	988	0 (1.0)	−1.0 (0.6)	−0.3 (0.7)	0.7 (0.9)
		%	%	%	%
Informant reports
Problems with depression (ages 18–38)	987	32.3	15.8	25.7	46.0
Problems with unreasonable fears (ages 18–38)	987	23.0	8.2	18.1	34.2
Problems with alcohol (ages 18–38)	987	14.4	1.8	10.3	23.8
Problems with drugs (ages 18–38)	987	12.2	1.8	6.4	22.4
Talks about suicide (ages 26–38)	974	3.5	0.6	1.7	6.5
Any problem (ages 18–38)	987	45.9	21.1	38.9	63.4