Depression
Depression is a disorder of mood. In other words, depression is a mood disorder – Depressive
Disorder.
Mood can be defined as a pervasive and sustained emotion or feeling tone that influences a person’s behavior and colours his or her perception of being in the world.
The term depression is extremely broad, variably defining an affect, mood states, disorders, or syndromes—as well as disease states.
A depressed ‘affect’ usually occurs in response to a specific situation and is defined as a transient and non-substantive state of feeling ‘depressed’, ‘sad’, or ‘blue’.
A depressed mood is more pervasive, more likely to be experienced as unusual or atypical, associated with negative ideation (e.g. hopelessness, helplessness, pessimism about the future), lowering of the self-esteem and may influence behaviour. It generally lasts only minutes to days.
A depressive disorder (Depression) is generally distinguished by a longer duration, more clinical (and more pathological) features, and distinct social impairment. It lasts a minimum of 2 weeks.
Symptoms of Depression
1. Depressed mood
2. Loss of interest and enjoyment
3. Reduced energy leading to increased fatiguability & diminished activity
4. Reduced concentration & attention
5. Reduced self-esteem & self confidence
6. Ideas of guilt and unworthiness
7. Bleak and pessimistic views of the future
8. Ideas or acts of self-harm or suicide
9. Disturbed sleep
10. Diminished appetite
Causes/ risk factors of Depression
Biological factors
1. Neurotransmitters : Neurotransmitters are chemicals in the brain found between neurons & they help in the transmission of signals from one neuron to another. There are many neurotransmitters like Serotonin, Norepinephrine, Dopamine, GABA, Acetylcholine, Glutamate, glycine – the balance of which are found disturbed in mood disorders, thus altering the signal transmission & thereby the connectivity between different brain regions.
2. Receptors : Different Neurotransmitters bind to specific receptors on the neurons to transmit the signals. In mood disorders, these receptors may be upregulated or downregulated or hypo-functional or hyper-functional for specific neurotransmitters
in specific brain regions.
3. Second Messengers and Intracellular Cascades : Each Neurotransmitter after binding to its specific receptor on the neuron, triggers the G Proteins & some enzymes causing the production of 2nd messengers such as cAMP & cGMP, which in turn regulate the function of neuronal membrane ion channels; thereby regulating the transmission of signals across neurons. In mood disorders, this complex machinery is found to be deranged.
4. Alterations of Hormonal Regulation : Various hormones like BDNF, Cortisol, Thyroid
hormone, Growth hormone are found to be dysregulated in Mood disorders.
5. Alterations of Sleep Neurophysiology: Normal sleep has different stages like REM & NREM (I-IV) electro-physiologically. In mood disorders, its deranged or fragmented.
6. Immunological Disturbance : Impaired cellular immunity – decreased ability of the
body to fight against germs, pathogens & diseases.
7. Structural and Functional Brain Imaging :
• CT & MRI Scans have shown that mood disorders damage different parts of the Brain, causing Neurodegenerative changes – Ventricular enlargement, cortical atrophy, sulcal widening & reduced hippocampal or caudate nucleus volumes.
• PET Scans have shown decreased brain metabolism, more on the left hemisphere of brain in depression & on the right hemisphere in mania. Evidence suggests that medications normalize these changes.
Genetic Factors
1. Family Studies : If one parent has a mood disorder, the child will have a risk of 10-25% for mood disorder. If both parents have mood disorder, this risk doubles. The more members of the family are affected, the greater the risk is to a child. The risk is greater if the affected family members are first-degree relatives rather than more distant relatives.
2. Twin Studies : If one Monozygotic (identical) twin has a mood disorder, there is 70 to 90 percent risk that the other twin will develop the same disorder. In the case of Dizygotic (fraternal) twins, the risk is 16-35%.
Psychosocial Factors
1. Life Events and Environmental Stress : Stressful life events more often precede the development of mood disorders. Stress results in long-lasting changes in the brain’s biology- alter the Neurotransmitter balance, intraneuronal signalling systems & even loss of neurons and synaptic contacts. As a result, a person has a high risk of developing subsequent episodes of a mood disorder, even without an external stressor.
2. Personality Factors : Persons with certain personality disorders— OCD, histrionic, and borderline – may be at greater risk for depression than persons with antisocial or paranoid personality disorder.
Diagnosing Depression
Depression is diagnosed by conducting a –
1. Psychiatric interview- of the client (patient) & informants (relatives). A detailed history of the complaints & the present illness, past history of psychiatric illness, family history to see if there are any genetic predisposing causes, personal history to see if any marital/relationship problems or any substance use like alcohol or if there are any external stressors like job loss contributing to the present illness, general medical history to rule out any possibility of any physical illness causing a secondary depression (like hypothyroidism/ vitD3 deficiency/parkinsonism/Dementia), assessment of personality to see if any personality traits or personality disorder is contributing to the current episode of illness.
2. Mental Status examination- General appearance & behaviour, Psychomotor activity, Talk, Thought, Mood, Affect, Perception, Cognitive functions- attention & oncentration, memory, intelligence, abstractability, judgment & insight are assessed.
3. Physical Examination- to see if the patient has any undiagnosed medical condition like
hypothyroidism, parkinsonism or any other neurological condition causing or
contributing to the present psychiatric illness.
4. Neuro-Psychiatric assessment scales- depression rating scales to have an objective
measurement of depression.
Investigations
Blood levels of Thyroid hormones, Blood vitamin D3 levels, Blood sugar levels etc to see if any physical illness is contributing or causing the depression.
Treatment of Depressive Disorder
A. Pharmacotherapy- It’s the treatment by using medicines- Antidepressants. Medicines correct the neurochemical imbalances, the receptor dysregulations, 2nd messenger & intracellular disarray, stops neuronal loss, increases neuronal dendritic spines and reestablishes neuronal synaptic connections and thus improves and normalises connectivity of different brain regions, thus improving the mood & cognitive symptoms of depression. CT, MRI, PET & FMRI studies have shown that treatment with drugs have a positive rebuilding effect on the brain. Antidepressants are safe, efficacious and are not addictive. Most of the antidepressants have no to minimal side effects. The duration of treatment depends on the duration of the illness, its severity, no of depressive episodes etc. It’s important to complete the full course of treatment and not to stop treatment after mere resolution of symptoms as premature termination of treatment can lead to illness recurrence. After each episode of depression, the illness severity increases, frequency of the episodes increases and the response to treatment decreases and thus there will be more residual symptoms.
There are various classes of Antidepressants. They are –
1. SSRIs – Specific Serotonin Reuptake inhibitors. Eg: Fluoxetine, Escitalopram
2. SNRIs – Serotonin Norepinephrine Reuptake inhibitors. Eg: Venlafaxine
3. NASSA – Norepinephrine and Specific Serotonin Reuptake inhibitors. Eg: Mirtazapine
4. NDRI – Norepinephrine Dopamine Reuptake inhibitor. Eg: Bupropion
B. Psychotherapy- Psychotherapy is the treatment by psychological means to overcome the patient’s problem. There are 3 types of psychotherapy which are useful in depression.
1. Cognitive Therapy- Correcting cognitive distortions (-ve thoughts)
2. Interpersonal Therapy- focusses on the patient’s current interpersonal problems.
3. Behaviour Therapy- Focusses on maladaptive behaviour patterns.
Reference :
1. Oxford Textbook of Psychiatry
2. Kaplan & Sadock’s Comprehensive Textbook of Psychiatry
3. The ICD-10: Classification of Mental and Behavioural Disorders
4. Diagnostic and Statistical Manual of Mental Disorders (DSM–5)
5. https://www.ncbi.nlm.nih.gov/pmc/
Self-Assessment
