Weissman et al. (2005)

aim

To investigate the potential genetic nature of Major Depressive Disorder (MDD)

method (3)

• longitudinal family study (over 20 years)

• Interviews

• Researcher triangulation

participants

sample of 161 grandchildren, their parents and grandparents

Original sample (6)

• Looked at families with high and low risk for depression

• Original sample of parents (the now grandparent) included 2 groups: 

  • Depressed grandparents - patients selected from an outpatient clinic that specialized in mood disorders

  • Non-depressed grandparents - selected from the same local community

• The original sample of parents and their children was interviewed 4 times during this period

  • These children, now parents, have children, allowing the 3rd generation to be studied

data collection

• data collected from clinicians, blind to past diagnosis of depression or data collected in previous interviews 

  • researcher triangulation→ evaluated by 2 experienced clinicians: a child psychiatrist and psychologist

(RESULTS) inter-rater reliability for major depressive disorder (MDD)

0.82

(RESULTS) inter-rater reliability for anxiety disorders

0.65

(RESULTS) inter-rater reliability for alcohol dependency

0.94

(RESULTS) Grandchildren with 2 Generations of MDD (3)

• had high rates of psychiatric disorders

  • By 12, 59.2% of the grand children were already showing signs of a psychiatric disorder (most commonly anxiety disorders)

• increased risk of any disorder

(RESULTS) General findings (2)

• Severity of the parent’s depression correlated with an increased rate of mood disorders in the children 

• No significant effect of parental depression on the grandchildren, if there was no history of depression in the grandparents

conclusion (2)

• Suggests that Major Depressive Disorder (MDD) may have a genetic component

• Indicates that the severity and family history of depression play a key role in a child’s mental health risk