The Sao Paulo Megacity is a multi-stage cross-sectional population-based epidemiological study designed to assess psychiatric morbidity in a representative sample of adult household residents aged 18 or older living in the Sao Paulo metropolitan area (SPMA), with a global response rate of 81.3% . Data were collected between May/2005 and April/2007 by trained lay interviewers, using the paper and pencil version of the World Mental Health Survey Composite International Diagnostic Interview (CIDI 3.0), a fully structured diagnostic interview that is composed of clinical and non-clinical sections arranged in Part I and Part II . Core disorders (anxiety, mood, impulse-control, and substance use disorders) and sociodemographic risk factors were assessed in all respondents (Part I sample). WMH-CIDI non-core clinical modules as well as non-clinical sections were administered in a subsample composed by all core disorder cases and a 25% random sample of non-cases (Part II sample). A total of 5,037 Part I and 2,942 Part II individuals were interviewed and we focus our analyses on the 491 Part II individuals with 12-mo MDD.
12-month Major Depressive Disorder
Major depressive episode among respondents who did not have a lifetime history of bipolar spectrum disorder  occurring in the 12 months prior to the interview were assessed through the CIDI 3.0 clinical sections, based on the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) diagnostic criteria (12-mo MDD) .
Severity of 12-mo MDD: MDD severity were classified into three categories: (1) severe if their depression resulted in severe role impairment (7-10 points) according to the Sheehan Disability Scale (SDS) ; (2) moderate if they reported moderate role impairment in the SDS (4-6 points), and (3) mild if they reported no or moderate role impairment (3 or less).
Respondents were asked how many visits in the past 12 months they made to a psychiatrist, medical doctor, psychologist, social worker, counselor, mental health professional, non-mental health professional, for any mental health or substance-use problems. They were asked also if they stopped seeing these providers, and if they completed the full recommended course of treatment.
Health treatment providers: Respondents were classified into two categories: (1) specialist mental health (SMH: psychiatrist, psychologist, other mental health professional in any setting, social worker, or counselor in a mental health specialized setting); and (2) general medical services (GM: primary care doctor, other medical doctor, any other healthcare professional seen in a GM setting). For the purposes of these analyses, we did not include or consider help sought from spiritual advisors or healers.
Contact coverage was defined as having had any contact with a SMH specialist or GM provider for a mental health condition in the past 12-months.
12-month contact coverage and treatment provided
If respondents saw a medical provider in the past 12 months, they were asked about type of treatment received, i.e., pharmacotherapy, psychotherapy, or both.
For each psychotropic medication used in the past 12 months, specific class of drug, dose, and duration were recorded . If respondents reported more than 3 medications, they were further asked about three random medications, out of the maximum of 10 reported, and medications were categorized as anti-Depressants, mood-stabilizers, anti-psychotics, and other (any other psychotropic medication). Respondents were then classified into two categories: (1) receiving any psychotropic medication; and (2) receiving any antidepressant. Respondents were also asked how many days out of 30 they either forgot to take the medication or took less than prescribed, in a typical month over the past 12 months. Patient adherence with medication use was defined as not having missed or taking less than was prescribed for 3 days or more in a typical month [35-37]. Medication control was classified as Adequate if respondents used any psychotropic medications and had at least four visits with any physician or psychiatrist [14, 38].
According to these variables several combinations were constructed, as follows:
Adequate pharmacotherapy: Classified as such if respondents were (1) taking antidepressants with adequate medication control by any physician and adequate patient adherence; or (2) taking any non-antidepressant psychotropic medication with adequate medication control by a psychiatrist and adequate patient adherence.
Pharmacotherapy for antidepressants: considered as (1) Partially adequate pharmacotherapy for any antidepressants, defined as having 2 of the 3 conditions: appropriate medication (antidepressants); and/or adequate medication control for the anti-depressant treatment; and/or patient adherence for the antidepressant use. (2) Adequate pharmacotherapy for any antidepressants: defined as having all 3 of the above-described conditions.
Any psychotherapy was considered if respondents had two or more visits to a psychiatrist for, on average, 30 or more minutes; or two or more visits to another SMH provider . The adequate number of sessions was defined as at least 8 sessions over the past 12 months [14, 38]. Psychotherapy adherence depended on whether the respondent prematurely ended treatment .
Adequate psychotherapy was considered if respondents had at least 8 sessions from a SMH provider; or if they are still in treatment after 2 visits. Visits to psychiatrists needed to last 30 minutes or more to be considered as psychotherapy (and not merely medication control) . Partially Adequate psychotherapy: Considered as above, but with a minimum of 5 sessions or 2 or more visits and still in treatment.
Effective coverage - Adequate combination of pharmacotherapy and psychotherapy
Effective coverage, i.e. an adequate treatment combination, was adjusted for MDD severity, and defined as (1) respondents with mild and moderate MDD having received adequate pharmacotherapy and/or adequate psychotherapy; or (2) respondents with severe MDD having received a combination of both adequate pharmacotherapy and adequate psychotherapy [14, 38-44].
Contact Coverage Cascade Framework
According to the variables described above, we developed the Contact Coverage Cascade Framework including adjustments for quality-of-care (inputs and processes) and user adherence (physician prescription, drug dosage, and early drop out) . To identify critical bottlenecks, we analyzed the relative size of each gap in the context of the whole effective coverage cascade and focused our analysis on gaps that represent a drop of 10 percentage points or more in overall coverage for MDD cases.
Descriptive statistics and measurements of associations were calculated applying survey sampling procedures that consider the complex sampling design, using weights to adjust for sampling probabilities and for the age-sex structure of the target-population; the Part II sample was further weighted for the under sampling of Part I respondents without core disorders .
The proportion estimates and standard errors of people with 12-mo MDD who received treatment were calculated using the Taylor series linearization method  implemented in SAS (version 8.2, SAS Institute, Cary, N.C.). Effects of weighting and clustering on significance tests for these subgroup differences were adjusted for using the Taylor series linearization method .
The statistical significance of differences in conditional treatment prevalence estimates by disorder severity was evaluated with logistic regression models, with dummy control variables for age, sex, and marital status. Statistical significance was evaluated using 0.05 level, two-sided tests.