IB PSYCHOLOGY ABNORMAL: ETIOLOGY

BIOLOGICAL CAUSES FOR DEPRESSION

The biological causes for depression are often studied through twin studies, longitudial studies, and correlations. Genes are looked at, the roles of genes and the environment, in addition to neurotransmitters and brain functioning.

BIOLOGICAL CAUSES FOR DEPRESSION

Kendler et al (2006)

Swedish twin study on heritability of depression in men/women

AIM: Investigate the genetic effects of Major Depressive Disorder in males and females, and across generations.

METHOD: 42,000 twins assessed for depression in computer-assisted telephone interviews

RESULTS: Heritability of depression was significantly higher in females than in males although no significant environmental or genetic differences found across generations

CONCLUSION: Researchers concluded that women are more sensitive to having a genetic predisposition for depression than men.

BIOLOGICAL CAUSES FOR DEPRESSION

Caspi et al (2003)

Serotonin 5-HTT gene's relation to depression

AIM: To investigate if stressful life events had an influence in depression in individuals with shorter alleles on the 5-HTT gene (which is a serotonin transport gene and is involved with reuptake of serotonin at the synapse)

METHOD: 1000 New Zealand children in longitudial study divided into 3 groups: (1) Both short alleles on 5-HTT, (2)One short allele and one long on 5-HTT, (3) Both long alleles. Stressful life events occurring between 21-26 years of age assessed and found no difference in number of stressful life events in all 3 groups.

RESULTS: Individuals with shorter alleles displayed more depressive symptoms to stressful life events when compared to same events in longer allele group. Those suffering 4 or more stressful events 33% of shorter allele groups developed depression compared to 17% of longer allele group.

CONCLUSION: Genes can predispose someone and if environmental triggers are present, it can be expressed--the study also supports a genetic basis for depression in addition to supporting serotonin's role in depression. The study though was correlational, therefore no causation.

COGNITIVE CAUSES FOR DEPRESSION

The cognitive causes for depression often focus around negative thinking patterns and the way we process information.

COGNITIVE CAUSES FOR DEPRESSION

Beck (1967)

Cognitive distortions and biases on how information is processed, our automatic thoughts as well.

-Our schema (self-concept) distorts how we process information, often negatively

-Depressed patients have negative cognitive thoughts and exhibit a negative triad characterized by

>The "self," or feelings of worthlessness

>The world, thinking that it affects everything in their lives

>The future thinking that things will only get worse and they can't change it

-Faulty thinking patterns as well that lead to cognitive biases

>Overgeneralization based on negative events

>Blaming oneself for everything (opposite of self-serving bias)

>Dichotomous thinking ("black/white thinking") and selective recall of negative consequences

COGNITIVE CAUSES FOR DEPRESSION

Alloy et al (1999)

Negative cognitive style affect depression

AIM: To see if cognitive style affected possible depression later on in life

METHOD: Conducted surveys on individual's thinking styles (either positive or negative in explaining life events) on college students in their early 20's. Placed in 2 groups (high risk and low risk based on cognitive style) and longitudinally studied for 5.5 years through self-report inventories, semi-structured interviews.

RESULTS: 1% of people in positive thinking groups developed depression and 17% of those in negative thinking group developed depression

CONCLUSION: Supports that cognitive style can be linked to depression and identifying that negative style can be preventative measure in developing depression

SOCIOCULTURAL CAUSES FOR DEPRESSION

The sociocultural causes for depression looks at prevalence rates across difference cross-sections of society to see if there are noticeable differences in rates for depression, and speculates on what the reason for differences might be.

SOCIOCULTURAL CAUSES FOR DEPRESSION

Kleinmann (1982)

Chinese depression patients and somatization.

Chinese patients express symptoms of depression physically (somatically), rather than symptomatically ("I am sad"). In China, as well as many other Asian cultures, there is still a stigma attached to mental disorders, so somatization serves as a coping mechanism because the group is more supportive and it allows relief.

-In China, depression might be described as back pain, or headaches, whereas in western culture it is described as sadness, guilt, and lack of motivation

-Culturally, clinicians need to be aware of the differences for diagnostic purposes, but it could also prevent someone from getting treatment if they do not recognize themselves as having a "mental disorder"

SOCIOCULTURAL CAUSES FOR DEPRESSION

Marsella (1979)

-Symptoms of loneliness, isolation, sadness are symptoms of Western civilization and individualistic cultures

-Collectivist cultures have larger social networks of support and express symptoms more somatically

SYMPTOMS OF MAJOR DEPRESSIVE DISORDER

Varies among individuals, genders, cultures, and age.

-Low mood lasting for a long time

-Lack of interest in formerly liked activities

-Weight change (gain or loss of more than 5% in a month)

-Insomnia or hypersomnia (sleep disturbances)

-Movement activity too slow or fast

-Feelings of worthlessness or guilt

-Diminished ability to think or concentrate

-Recurrent suicidal thoughts or ideation

PREVALENCE RATES OF MAJOR DEPRESSIVE DISORDER

-In a 2003 comparison, it was found lifetime prevalence ranging from 1% in Czech Republic to 16.9% in USA

-Lifetime prevalence often higher in high-income countries (may be several factors relating to difference)

-2015 survey in USA indicated 12 month prevalence of adults (people suffering from depression within that 12 month span) was 6.7%, women at 8.5%, and men at 4.7%

-Women consistently at risk 2 times as often as men (related to stressors, hormones, care for children, responsibilities, abuse)

-Cross-cultural differences indicate onset is greater ranging from adolescence to mid-40's, most often though in 20's