Life events and early onset depression: cause or consequence?

BACKGROUND: Adverse life events prior to episodes of depression are assumed to play a causal role. Earlier studies have, however, not adequately controlled for the potential confounding effects of previous depression. METHOD: A two-phase study was nested within a six-wave population based cohort study of 1947 adolescents. Interviews at two assessment phases with the CIS-R and CIDI were used to generate ICD-10 diagnoses of depressive disorder. Life events with longer-term contextual threat were reported for the 6 months before first diagnosis and categorized on the basis of participant appraisal as negative and neutral/positive in effects. Previous depressive and anxiety symptoms were measured 6 months earlier. RESULTS: Pre-existing depressive and anxiety symptoms predicted later events, increasing three-fold the risks for both neutral/positive and negative events in females and increased seven-fold the risk of negative events in males. Life events in turn predicted the onset of depressive disorder independently of previous symptoms. Single negative events held an over five-fold elevated risk and multiple events an almost eight-fold higher risk. Personal threat and loss were associated with disorder in females but not males. CONCLUSIONS: The findings are consistent with a causal role for life events in early episodes of depression. The association also reflects a reciprocal relationship in which earlier symptoms predict later events, perhaps as a result of an individual's attempts to change unfavourable social circumstances.

Parental 'affectionless control' in adolescent depressive disorder.

BACKGROUND: Adults with depressive disorder report high rates of sub-optimal maternal care in childhood. Despite the greater salience of relationships with parents earlier in life, associations with parenting style have not yet been systematically studied in adolescent onset disorder. METHODS: A six-wave, 3-year study of adolescent health in 2032 Australian secondary school students provided an opportunity to undertake a two-phase study of early onset depression. Between waves 2 to 6, a self-administered computerised form of the revised Clinical Interview Schedule (CIS-R) was used to generate a first phase diagnosis of ICD-10 depressive episode. Each subject with a CIS-R-defined depressive episode was selected for second phase assessment together with two subjects from the CIS-R non-cases in each school. Second phase assessment included a second diagnostic assessment using the depression and hypomania modules of the Composite International Diagnostic Interview (CIDI) and assessment of paternal and maternal style using the Parental Bonding Instrument. RESULTS: A total of 1947 out of 2032 subjects in the sampling frame (95.8%) participated in the cohort study (phase 1) at least once; 406 (94%) of the 435 selected subjects completed second phase assessment. One hundred and nineteen subjects fulfilled criteria for depressive episode on the CIS-R at one or more waves. Over the 30-month study period, 69 subjects (10 male, 59 female) fulfilled both CIS-R and CIDI definitions of depression at the same wave and were classified as 'definite depressive disorder'. Low maternal and paternal care held independent associations with both definitions of depression, with the effects clearest in those in the lowest quartile of reported care. After adjusting for low parental care, the associations between high parental control and depression were small. CONCLUSIONS: Sub-optimal parenting is associated with depressive disorder in adolescents. Low maternal and paternal care are each associated with a two- to three-fold higher rate of depressive disorder. These findings are consistent with an effect of sub-optimal parenting on the onset rather than course of disorder. Whether sub-optimal parenting is associated with a risk for the onset of depression outside the adolescent years has yet to be clarified.

Adolescent depressive disorder: a population-based study of ICD-10 symptoms.

OBJECTIVE: Earlier studies have suggested that symptoms of depressive disorder in adolescents may differ from those found in adults. Even so, diagnostic criteria developed in adults have come to be widely applied to younger subjects. This study examines the frequency of ICD-10 symptoms in depressive disorder and their association with severity in a large community sample of adolescents aged 15 to 18 years. METHOD: A six-wave prospective study of adolescent health and emotional wellbeing in 2032 Australian secondary school students provided an opportunity to conduct a two-phase study of adolescent onset depression. A self-administered computerised form of the revised Clinical Interview Schedule (CIS-R) was used as a first phase diagnostic measure. Second phase assessment using the Composite International Diagnostic Interview (CIDI) allowed the delineation of a group fulfilling criteria on both instruments. The ICD-10 symptoms and severity profiles for depression were generated with standard algorithms. RESULTS: 1947 (95.8%) out of 2032 subjects in the designated sample completed phase 1 assessment at least once. Participation rates at phase 2 interviews were 93%. Over the 30-month study period 69 subjects (10 male, 59 female) fulfilled criteria for ICD-10 depressive episodes on both the CIS-R and CIDI. Thirty-one per cent (n = 21) had experienced a severe episode, 46% (n = 32) moderate and 23% (n = 16) mild episodes. Loss of interest and pleasure, decreased energy and fatigue, sleep disturbance, suicidal ideation and diminished concentration most clearly distinguished adolescents with depressive disorder from controls. Self-reproach and guilt, psychomotor agitation and/or retardation and appetite disturbance with weight change showed the clearest increase in frequency with increasing severity of episode. The somatic syndrome was reported by close to one in three of those with a severe depressive episode, but was uncommon in those with mild and moderate episodes. CONCLUSIONS: The ICD-10 diagnostic criteria are applicable to depressive disorder in older adolescents. With the exception of depressed mood, found in one in five non-cases, all other symptoms were common in cases and uncommon in non-cases. Practitioner awareness of symptoms indicating the presence and severity of disorder should enhance early identification and choice of treatment in adolescent depression.

A computerised screening instrument for adolescent depression: population-based validation and application to a two-phase case-control study.

Computer-administered questionnaires have been little explored as a potentially effective and inexpensive alternative to pencil and paper screening tests. A self-administered computerised form of the revised Clinical Interview Schedule (CIS-R) was compared with the Composite International Diagnostic Interview (CIDI) in a two-phase study of 2032 Australian high school students (mean age 15.7 years) drawn from a stratified random sample of 44 schools in the state of Victoria, Australia. Prevalence, sensitivity and specificity were estimated using weighting to compensate for the two-phase sampling. Point prevalence estimates of depression using the CIS-R were 1.8% for males and 5.6% for females--an overall prevalence of 3.2%. Prevalence estimates for depression in the past 6 months using the CIDI were 5.2% for males and 16.9% for females--an overall estimate of 12.1%. The CIS-R had a positive predictive value (PPV) of 0.49 and negative predictive value (NPV) of 0.91 for CIDI depression in the past 6 months. Specificity was very high (0.97) but sensitivity low (0.18), indicating that a majority of those with a CIDI-defined depressive episode in the past 6 months were not recognised at a single screening using the CIS-R. Even so, the CIS-R has proved at least as good as any pencil and paper questionnaire in identifying cases for nested case-control studies of adolescent depression. Further exploration of strategies such as serial screening to enhance sensitivity is warranted.