Affective Disorders: Depression

Terminology Symptomology identification of symptoms Etiology why people have symptoms Prevalence rate % of population with the disorder Lifetime prevalence % of population who will get the disorder over their lifetime Onset age Average age on start of disorder

Focusing your studying Must learn two disorders well enough to write 22 point essay answers Select one disorder from two of the following groups Anxiety disorders (PTSD) Affective disorders (depression) Eating disorders (bulimia)

Depression Affective disorder: major depressive disorder Diagnosed when person has 2 weeks of depressed mood or loss of interest and pleasure Plus four of Insomnia Appetite changes Loss of energy Feelings of worthlessness Thoughts of suicide Difficulty concentrating

Depression Common 15% will have MDD as some time in their lives 25% of admissions to UK psych hospitals 2-3 times more common in women More likely in low socio-economic populations Most frequent in young adults Above average numbers in Jewish males where they match number of females A recurrent disorder (lasts 3-4 months)

Chronic Depression Lasts for two or more years Requires hospitalization and treatment

Consider the fact that Many people who experience high stress and nasty events do not become depressed! Research is pointing to several relevant features of brain function cognitive flexibility - our capacity to adapt our thinking to different situations how our brains concentrate on processing and remembering happy, as opposed to sad, information.

Biological Research Twin studies (Nurnberger and Gershon, 1982) high concordance of MZ over DZ Possible genetic predisposition Neurotransmitters and hormones Duenwald (2003) Short variant of 5-HTT gene (serotonin levels)

Biological Research Schildkraut (1965) Catecholamine hypothesis Low levels of noradrenalin affect mood Developed into idea that low levels of serotonin affect mood Janowsky Physostigmine induced profound depression and suicidal thoughts Delgado and Moreno Found abnormal levels of noradrenalin and serotonin

Chicken and egg problem Which came first the depression or the abnormal levels of neurotransmitters? we can’t measure levels of serotonin in live human brains Focus on the process of transmission not the specific transmitters

Role of Cortisol High levels of cortisol (stress hormone) Lowers density of serotonin and impairs function of noradrenaline BUT Relationship between stress and depression is not understood as it is not causal

Cortisol Stress hormones (glucocorticoids) – fear, anxiety and manifest as some of the symptoms of depression Regulate serotonin, noradrenaline and dopamine

More support for biology Cushing syndrome- high % are depressed Excessive cortisol produced When given medication to normalize cortisol the depression disappears

Cognitive explanations of depression Depressed people think depressed thoughts Depressed mood leads to cognitive symptoms Depressed cognitions, cognitive distortions and irrational beliefs Ellis (1962) cognitive style theory Psychological disturbances come from Irrational and illogical thinking People drawing false conclusions Producing feelings of anger, anxiety and depression

Distortions of Schema Beck (1976) Depressed people have developed abnormal schema of self which can interfere with information processing Depressed people have a negative cognitive triad Overgeneralization based on negative events Non-logical inference about themselves Dichotomous thinking- black and white- with selective recall

Attribution of meaning Depressed people over react with negative expectations about the future Explain things in terms of internal, stable and global factors Irrational beliefs lead to cognitive bias’ Extreme self-criticism and pessimism results

Prospective Studies Look for people with negative/depressive thinking styles and watch them over time Alloy et al (1999) 6 year study Found only 1% of non- negative thinkers depressed 17% of negative thinkers developed depression ? link between cognitive style and depression Chicken and egg problem-which came first

Sociocultural Factors Brown and Harris (1978) 29/32 women who became depressed had severe life event But 78% of women who had a severe life event DID NOT become depressed Life events can trigger depression- vulnerability model Lack of employment Absence of social support Young children at home Loss of mother at an early age Childhood abuse

Diathesis- Stress Model Depression due to pre-existing biological tendency triggered by life events

Sociocultural research World Health Organisation (WHO) 1983 Found common symptoms in four countries (Iran, Japan, Canada, and Switzerland) Sad affect, loss of employment, anxiety, tension, lack of energy, loss of interest, inability to concentrate, ideas of insufficiency and worthlessness Depression can be expressed in different ways Headaches, somatic symptoms- Collective societies Affective symptom- Individualistic societies

Gender Considerations Women two to three time more likely to become clinically depressed (Williams and Hargreaves, 1995) More emotional ? More socially acceptable ?

Evaluate Research Read Brown and Harris (1978) on page 156 and evaluate the research based on Methodology Validity Reliability Ethics Bias