WHAT IS IT?
Major depressive disorder (MDD) is a mood disorder characterized by patient reported depression and it is believed that patients with this condition have lowered levels of certain neurotransmitters in the brain (such as serotonin, norepinephrine, and dopamine). Patients experience depressive episodes that usually last 6-12 months.
WHY IS IT A PROBLEM?
Decreased levels of serotonin will lead to a depressed mood which in turn can affect one’s quality of life in a variety of ways (symptoms explained more below).
WHAT MAKES US SUSPECT IT?
Risk factors: female, family history, trauma, stressful life events, chronic medical illness
Chief complaint: many patients don’t complain directly of depression/loss of interest in activities. Instead the below are some common chief complaints that can be suggestive of an underlying MDD:
- Chronic fatigue, or fatigue present ≥ half the time for ≥ 1 month
- Multiple medical visits (≥ 5 per year)
- multiple idiopathic symptoms
- irritable bowel syndrome
- sleep disturbance
- memory or cognitive complaints (difficulty concentrating or making decisions)
HOW DO WE CONFIRM A DIAGNOSIS?
Depressive episodes are characterized by 5 of the following 9 symptoms for at least 2 or more weeks (SIGECAPS pneumonic). One of the symptoms must also be either depressed mood or loss of interest:
- Sleep disturbances
- Loss of interest (anhedonia) in usual hobbies
- Guilt or feelings of being worthless
- Energy loss/fatigue
- Concentratoin problems
- Appetit/weight changes
- Psychomotor retardation/agitation
- Suicidal ideations
- Depressed mood
Sleep changes (can be observed with sleep studies):
- Decreased slow wave sleep
- Decreased REM latency
- Increased REM early in sleep cycle
- Increased total REM sleep
- Recurrent nighttime awakenings
- Early-morning wakening (with difficulty going back to sleep)
HOW DO WE TREAT IT?
First line therapy:
Cognitive Based Therapy (CBT): this is a form of behavioral therapy that is designed to give the patient tools/strategies to address their current problems (i.e. coping strategies, reconditioning though processes, etc).
Selective seretonin re-uptake inhibitors (SSRIs): these medications inhibit the re-uptake of serotonin in the neural cleft, resulting in increased serotonin signaling.
Serotonin norepinephrine reuptake inhibitors (SNRIs): similar to SSRIs however these medications also inhibit re-uptake of norepinephrine.
Mirtazapine: noradrenergic and specific serotonergic antidepressant (NaSSA) that acts by antagonizing the α2-adrenergic receptor and certain serotonin receptors (those involved in negative feedback). This ultimately leads to increased serotonin and adrenergic signaling,
Bupropion: a weak norepinephrine-dopamine reuptake inhibitor (NDRI). This medication can also suppress appetites.
Electroconvulsive therapy: shock therapy that is used to trigger seizures in patients. While effective this is used as more of a last resort given the side effect of retro-grade amnesia
HOW WELL DO THE PATIENTS DO?
50% patients with depression may still have diagnosis of depression 1 year later (source).
WAS THERE A WAY TO PREVENT IT?
Psychological intervention (such as CBT) if used properly early on in higher risk individuals might be preventative of MDD.
WHAT ELSE ARE WE WORRIED ABOUT?
Suicide: Depression associated with 4 times higher risk of suicide than general population (source). MAKE SURE TO ASK IF PATIENT HAS CONTEMPLATED/ATTEMPTED SUICIDE
OTHER HY FACTS?
Older antidepressant drugs:
Tricyclic antidepressants (TCAs): block re-uptake of nonorepinephrine and serotonin. These can cause QT prolongation and cardiac arrhythmias.
Monoamine oxidase inhibitors (MAOIs): these medications prevent the breakdown of serotonin, norepinephrine, and dopamine. Risk of serotonin syndrome (increased heart rate, blood pressure, vomiting, diarrhea, clonus, all associated with too much serotonin signaling) when combined with tyramine (promotes serotonin endogenously) containing foods (such as smoked meats or cheeses).
Decreased 5-hydroxyindoleacetic acid (5-HIAA) in the CSF is a predictor for suicide risk in patients with depression. This is a major metabolite of serotonin.
Page Updated: 12.11.15