Depression is a complex mental health condition that goes beyond temporary feelings of sadness and emotional low points. Clinically, it’s recognized as a mood disorder due to its severe impact on an individual’s ability to function socially, physically, and mentally.
Depression can manifest as consistent low mood, persistent feelings of sadness, loss of interest in activities once enjoyed, difficulties with memory and thinking, as well as loss of appetite.
Causes of depression vary from brain chemistry (imbalance of neurotransmitters) and genetics to stressful life events and medical conditions. Although anybody can be affected by depression, the way it presents and its severity depend significantly on social, biological, and psychological factors.
While often minimized and misunderstood, depression is a leading cause of disability worldwide. A recent study by the Centers for Disease Control and Prevention (CDC) showed that around 13.1% of US adults and adolescents had depression in a given two-week period. However, researchers believe that these results are lower than reality, as many people don’t seek support and medical help with depression due to social stigma.
DSM-5 definition
According to DSM-5, Major Depressive Disorder is diagnosed when one or more Major Depressive Episodes occur with at least two weeks of persistent symptoms. In order to be diagnosed, an individual needs to experience at least five symptoms, including depressed mood or loss of interest in nearly all activities.
Other symptoms include:
- Significant weight loss or gain.
- Psychomotor agitation or retardation (restless movement or slowed movement and decreased verbal and facial output).
- Fatigue or loss of energy.
- Feelings of worthlessness or excessive guilt.
- Insomnia or hypersomnia.
- Decreased ability to concentrate.
- Recurrent thoughts of death or suicide.
Importantly, these symptoms need to cause significant distress and can’t be attributed to another medical condition or medication. In cases of grief or significant loss, clinicians use careful judgment in order to distinguish between a normal reaction and pathological depression.
DSM-5 also classifies different subtypes of MDD, depending on the context:
- Seasonal Affective Disorder (SAD) – linked to seasonal changes, symptoms usually emerge during winter or fall months.
- Prenatal and Postpartum Depression – symptoms occur during pregnancy or within four weeks of giving birth (in DSM-5 this is referred to as “MDD with peripartum onset”).
- Atypical Depression – temporary mood improvement as a response to a positive event (mood reactivity), in addition to increased sensitivity to rejection.
Other types of depressive disorders
In addition to Major Depressive Disorder, other types of depressive disorders include:
- Persistent Depressive Disorder (PDD) – a chronic but less severe form of depression that lasts for at least 2 years.
- Disruptive Mood Dysregulation Disorder (DMDD) – chronic irritability and frequent, severe temper outbursts usually manifested in children under 10 years old.
- Premenstrual Dysphoric Disorder (PMDD) – an intensified form of premenstrual syndrome (PMS) that includes mood changes such as extreme irritability, anxiety, or depression, which resolve shortly after menstruation begins.
- Depressive Disorder due to another medical condition – medical conditions such as Parkinson’s disease, hyperthyroidism or cancer can lead to depression.
Symptoms
Although DSM-5 has certain criteria to diagnose depression, symptoms can be very individualized and vary in type and severity.
Common symptoms include:
- Persistent sadness.
- Feelings of emptiness.
- Feelings of hopelessness, guilt, and worthlessness.
- Suicidal ideation.
- Irritability.
- Difficulty concentrating.
- Memory issues.
- Indecisiveness.
- Loss of motivation.
- Decreased productivity.
- Sleep disturbances.
- Appetite changes.
Treatment methods
Treatment of depression requires a very individualized approach, usually including a combination of psychotherapy, pharmacotherapy (if necessary), lifestyle changes, and in some cases, more advanced treatments, which we have explained below.
Psychotherapy
Cognitive Behavioral Therapy (CBT) helps individuals struggling with depression to identify problematic cognitive patterns and modify them. It is one of the most evidence-based treatments for depression.
Interpersonal Therapy (IPT) focuses on an individual’s interpersonal relationships by motivating them to resolve conflict and/or improve communication. It is very effective in cases of depression caused by personal losses or life transitions.
Psychodynamic Therapy focuses more on an individual’s past (childhood experiences and developmental history) and how their unconscious processes can cause emotional conflicts. By bringing these unconscious patterns into awareness, this type of therapy helps individuals better understand and resolve the underlying causes of their current difficulties.
Pharmacotherapy – antidepressants
Pharmacotherapy for depression involves several classes of antidepressants, each targeting brain chemistry in different ways to alleviate symptoms.
Selective Serotonin Reuptake Inhibitors (SSRIs) are usually the first line of treatment in severe cases due to their effectiveness and minimal side effects in comparison with other medications. They work by increasing serotonin in the brain.
Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) increase both serotonin and norepinephrine in the brain. Used when SSRIs are not effective.
Tricyclic Antidepressants (TCAs) are an older class of antidepressants that is used less frequently due to their side effects. They target serotonin and norepinephrine just like SNRIs, but have more side effects.
Atypical Antidepressants are used when other treatments prove ineffective. Each medication in this category affects different brain chemicals or pathways, depending on its specific mechanism of action.
Lifestyle changes
Lifestyle changes can complement medical and psychological treatments for depression. These changes focus on improving physical health, reducing stress, and supporting emotional resilience.
Patients are often encouraged to:
- Exercise more and potentially take part in movement therapies
- Ensure balanced nutrition and reduce intake of processed food
- Target stress reduction through mindfulness, yoga, and breath work
- Improve sleep cycles
Advanced treatment – Brain Stimulation Therapy
Advanced brain stimulation therapies are considered when other treatments for depression have not been effective. These approaches use targeted electrical or magnetic stimulation to influence brain activity and improve a patient’s mood.
Electroconvulsive Therapy (ECT) is a procedure where a small electrical stimulus is used to cause a brief seizure. Used only in very severe cases of treatment-resistant depression—usually when psychotic features or suicidality is present.
Transcranial Magnetic Stimulation (TMS) is a type of non-invasive brain stimulation involving magnetic fields. It works by delivering repeated magnetic pulses to specific brain regions—most often the left dorsolateral prefrontal cortex—to modulate neural activity and improve mood regulation.
Vagus Nerve Stimulation (VNS) uses an implantable device to stimulate the vagus nerve in the neck. The electric pulse travels to the brain, where it gets dispersed and targets different areas in order to change how brain cells work. This stimulation is thought to alter neurotransmitter levels and improve communication between brain regions involved in mood control.
Further resources and helplines
- Lifeline Chat https://chat.988lifeline.org/
- Veterans Crisis Line https://www.veteranscrisisline.net/
- CDC – Depression Prevalence in Adolescents and Adults https://www.cdc.gov/nchs/products/databriefs/db527.htm
- National Institute of Mental Health – Depression Overview https://www.nimh.nih.gov/health/topics/depression
- American Psychiatric Association – Depression https://www.psychiatry.org/patients-families/depression
