Symptomatology and diagnostic criteria
A group of heterogenous disorders that are characterized by mood, drive and cognition.
The typical signs and symptoms of depression are
• Low mood
• Reduced affective responsiveness
• Lack of drive and initiative
• Negative cognitive evaluation of circumstances and self (eg, feeling worthless and/or
• Could also include somatic symptoms
o Weight loss
o Sleep disturbances
o Other disturbances of the circadian rhythm
o Constipation, irritable bowel syndrome or other vegetative dysfunctions.
Mania is typically associated with elevated, sometimes irritable mood, increased drive and
accelerated cognition to the point of flight of ideas and a sense of grandiosity.
Depression and mania may be accompanied by psychotic symptoms such as delusions and
hallucinations. In depression, mood congruent delusional themes include guilt,
impoverishment, hypochondriasis or Cotard syndrome.
The presence of psychotic symptoms make it sometimes difficult to distinguish the classical
mood disorders from schizoaffectic disorder.
“Dysthmic disorder” > milder form of depression which can take a chronic course over at
least two years. Dysthymia and recurrent major depressive episodes may cooccur and be
more prevelant in patients who are hospitalized for depression.
“Cyclothymia” > milder mood swings between the hypomanic and the depressive pole.
Mixed episodes could include a different mixture of moods, drives and thoughts, the most
common of the mix is agitated depression.
Depression and mania may also have catatonic features.
Major depression is very common across populations and cultures.
Lifetime prevelance between 4% and 20%, with women being twice as often affected as men.
5% to 10% will develop major depression within a 1 year period.
Age at onset peaks around the fourth decade, with a second peak in the sixth decade.
Dysthymia prevelance rate of 2% to 5%. The population risk for bipolar affective disorder is estimated between 0.5% and 1.5%.
Genetic Risk Factors
Both unipolar depression and bipolar affective disorder are associated with genetic risk
factors, but heritibility is considerably higher in bipolar disorder.
First degree relatives of patients with unipolar depression have a relative risk for the disorder
that is between 1.5 to 3 fold higher than the population risk.
MZ twins > 40%
DZ twins > 20%
Prepubertal onset of depression is probably less genetically mediated compared with onset
later in life.
Rather, adverse environmental events are apparently more important in earlyonset
There is additive genetic and environmental contributions to the vulnerability for depression.
The risk for bipolar affective disorder is about 7 fold increased for first degree relatives of
patients with bipolar disorder.
MZ twins > 60%
DZ twins > 25%
Major depression is a highly heterogeneous disorder.
There is a role for serotonin receptor polymorphisms (5HT2A) in the aetiology of unipolar
depression, particularly if associated with suicidal behaviour.
A polymorphism of the serotonin transporter gene has been linked with increased risk for
The FKBP5 gene regulating expression of glucocorticoid receptors is apparently associated
with recurrence of depression, but also with good response to antidepressants and frequent
Environmental Risk Factors
Losses of imporatnt relationships by death or seperation represent life events that may cause
depression in vulnerable people. Especially the loss of the primary caregiver (the like mother)
prior to the onset of puberty dramatically increases the risk of depressive episodes later in
Loss of work and poverty are also important risk factors for depression as are lack of social
support, physical illness and age.
During gestation and the postpartum period, depression is particularly linked with teenage
pregnancy, undesired pregnancy, unmarried states, separation, divorce or marital conflict. Pathophysiological mechanisms
Affective disorders are though to arise from complex dysregulations of neurotransmitter
systems, among which the catecholamines and serotonin are considered to be more important.
The catecholaminedepleting drugs such as reserpine may cause depression. Depression is
also associatedwith reduced serotonin availibilty in several key areas of the brain including
the hippocampal formation and the amygdala.
Norepinephrine has also been found to be reduced.
Dopamine availability appears to be diminished in depression, whereas in mania dopamine is
Exposure of the developing brain to chronic stress has neurotoxic effects, corisol and
corticotropin releasing hormone are reduced in some patients with depression.
There is an overall reduction of brain volume by 10% to 20% of the hippocampal formation
and the caudate region in depression, which correlates with the severity, duration and number
of depressive episodes.
Grey matter and neuropil are also dimished in the orbitofrontal cortex, prefrontal cortex and
the anterior cingulate cortex in depression.
However, the majority of pateints with bipolar affective disorders experience more depressive
episodes than manix episodes such thta the specificity of alterations at the transmitter or
anatomical level is less clear.
Depressed individuals display non verbal signals typical of submissive behaviour.
Depressed patients often avoid eyetoeye contact, show little movements of eye and mouth
region, reduce the amount of speech and affective tone of voice.
Nonverbal behaviours aim at reducing aggression of others that could be oriented towards
the self, and avoiding harm by displaying deescalation appeasement strategies in situations
of (perceived) defeat or inferiority.
That depressed individuals do not display the same behaviour in every social interaction.
They may show signs of aggression oriented towards family members, especially spouses or
children, from whom they demand instant support.
Submission and dominance are inherent to socially living species with complex hierarchies
Asymmetries in social status and competition for resources and mates, social rank and
relationships need to be negotiated.
In ancestral environments, social exclusion from the community was probably one of the
most important real threats to an individual, and potentially equivalent to a death sentence. A decision over fight or flight critically depends on the evaluation of one’s own power and
potential alliances, and in situations where success is unlikely or escape impossible,
submission and acceptance of suborination may be best option, at least for the moment being.
Depression primarly occurs in social or interpersonal context, but usually not according to
losses in nonsocial domains.
Again extremes of variation of low mood, including inappropriate contextual occurence,
abnormal intensity of duration are chracteristic for clinically relevant depression.
Humans are highly socially investing beings, in both kin and nonkin, but of course also
eager to receive returns on their investment.
In order to minimize the ris