NAMCS recorded all medications that were ordered, supplied, administered, or continued during each visit. Up to six medications were recorded in each visit in NAMCS 1996–2002. Starting in 2003, the maximum number of medications recorded was increased to eight. To make the years comparable, we limited the maximum number of medications to six in all years. ADHD medications included amphetamine, amphetamine/dextroamphetamine combination, atomoxetine, clonidine, dexmethylphenidate, dextroamphetamine, guanfacine, methylphenidate, and pemoline. We included clonidine and guanfacine as psychotropic medications only if the patient did not have hypertension. Antidepressants included amitriptyline, amoxapine, bupropion, citalopram, clomipramine, desipramine, doxepin, duloxetine, escitalopram, fluoxetine, fluvoxamine, imipramine, isocarboxazid, maprotiline, mirtazapine, nefazodone, nortriptyline, paroxetine, phenelzine, protriptyline, selegiline, sertraline, tranylcypromine, trazodone, trimipramine, and venlafaxine. Antipsychotic medications included aripiprazole, chlorpromazine, clozapine, fluphenazine, haloperidol, loxapine, mesoridazine, molindone, olanzapine, perphenazine, pimozide, quetiapine, risperidone, thioridazine, thiothixene, trifluoperazine, triflupromazine, and ziprasidone. Prochlorperazine, promethazine, droperidol, and prochlorperazine, which are primarily used for non-psychiatric indications, were not included. Mood stabilizers included carbamazepine, lamotrigine, lithium and valproate/divalproex. We included anticonvulsants (carbamazepine, lamotrigine, valproate/divalproex) as psychotropic medications only if the patient did not have a seizure disorder diagnosis. Sedative-hypnotics included alprazolam, butabarbital, chloralhydrate, chlordiazepoxide, chlorazepate, clonazepam, diazepam, diphenhydramine, esczopiclone, estazolam, flurazepam, hydroxyzine, lorazepam, meprobamate, nitrazepam, oxazepam, phenobarbital, secobarbital, temazepam, triazolam, zaleplon, and zolpidem. We included phenobarbital as a psychotropic medication only if the patient did not have a seizure disorder diagnosis. Psychotropic visits were classified into single-class psychotropic pharmacy visits, in which the patient was prescribed psychotropic agent(s) from only one medication class (ADHD medications, antidepressants, antipsychotics, mood stabilizers and sedative-hypnotics), and multi-class psychotropic visits, in which the patient was prescribed two or more psychotropic agents from across different psychotropic medication classes.
Mental disorder diagnoses were recorded based on ICD-9-CM codes (290–319). Up to 3 diagnoses were recorded for each visit. Specific diagnoses were classified into 5 broad categories: (i) disruptive behavior disorders [ICD-9-CM: 312.0–312.2, 312.30–312.38, 312.4–312.9, 313.81, 313.89, 314.0, 314.2–314.9], (ii) mood disorders [ICD-9-CM: 296.0–296.9, 300.4, 301.13, 311], (iii) anxiety disorders [ICD-9-CM: 293.84, 300.0–300.02, 300.09, 300.2, 300.21–300.23, 300.29, 300.3, 300.7, 308.0–308.9, 309.21, 309.81, 312.39, 313.0, 313.21, 313.23], (iv) adjustment disorders [309.0–309.9, except 309.21, 309.81], and (v) pervasive developmental disorders (PDD), mental retardation (MR), and psychotic disorders [ICD-9-CM: 291.0–295.9, 297, 298.0–298.9, 299, 301.2–301.22, 314.1].
Primary source of payment was classified as private insurance, public insurance, self-pay or “other”.
Other variables used in multivariate analyses included patient’s age group (6–12 years vs. 13–17 years), sex, race-ethnicity (white vs. minority), number of mental disorder diagnoses (1 vs. ≥ 2 diagnoses), visit status (returning patient vs. new patient), and physician specialty (psychiatry and psychiatric subspecialties vs. all others).