Many people worldwide are affected by the major depression disorder. It is a common and severe mental health condition. It is the most common mental condition which cover gender, age, and ethnicity. MDD have a variety of symptoms which include changes in eating and sleep patterns, concentration, and energy levels. This can affect the daily life functions. 

This disease can affect the relationships of people, physical health and mental health, and life quality.  

The lifetime incidence of MDD is about 5 to 17 %. The average incidence of MDD is about 12 %. MDD can affect all the individuals at any age, but usually it affects the late adolescence to early adulthood. The probability of a diagnosis of MDD is nearly double in females than in males. Hormonal. Biological, and sociocultural factors may affect the gender variations in MDD. The risk of MDD is also affected by the socioeconomic situations. People who are from lower socioeconomic backgrounds are at high risk of MDD because of the restricted access to the healthcare facilities and economic gaps. 

The incidence and prevalence rate of MDD may vary between regions and countries. This variations are because of the socioeconomic status, healthcare access, and cultural norms. The risk factors of MDD are family history, genetics, traumatic life events, personality, and chronic stress. 

Neuroendocrine Dysregulation: 

Hypothalamic-Pituitary-Adrenal (HPA) Axis: The HPA axis dysregulation is a neuroendocrine disease. It can cause the overproduction of stress hormone cortisol. Extended exposure to the high level of cortisol can lead to the changes in mood and cognitive function. This will contribute to the development of depression. 

Neurochemical Imbalances: 

Dysregulation of neurotransmitters: As per the one leading hypothesis, pathophysiology of depression is a neurotransmitters dysregulation like norepinephrine, serotonin, and dopamine. Decreased level of neurotransmitters in the brain areas may lead to the mood changes and symptoms of depressions. 

Inflammatory Processes: 

As per the research, which is conducted nowadays, there is a connection between depression and inflammation. Chronic or severe inflammation leads to increased level of inflammatory markers like cytokines. This can lead to symptoms of depression. Inflammatory mechanism may affect the neural plasticity and neurotransmitter metabolism.  

Environmental Factors and Genetic factors: 

Stressful life and trauma I the childhood or adult hood may increase the risk of depression. Depression is inherited disease. Various genes play an important role in the susceptibility of depression, and each gene has a little impact.  

Biological Factors: 

Neurotransmitter Imbalance: The biological factors in MDD are the imbalance in neurotransmitter in brain. Neurotransmitters like serotonin, norepinephrine, and dopamine pay an important role in the regulation of mood, Any imbalances in these neurotransmitter can lead to development of symptoms of depression. 

Genetic Factors: 

Any family history of depression may increase the risk of development of MDD. Genetic study has identified a particular gene variations which may predispose to the depression. 

Psychological Factors: 

Cognitive factors like negative thoughts, limited thinking and cognitive bias can lead to the development and prolonged symptoms of MDD. Cognitive behavioral therapy (CBT) is a regular treatment option for MDD.  

Environmental Factors: 

Stressful life, trauma, chronic stress, losing the loved one, major life changes, and financial difficulties may lead to the episodes of MDD in the individuals. Childhood adversity like neglection, abusing experience, or any other adverse events may increase the risk of development of MDD in later life. 

Psychological factors like stressors, life events, and social support may impact the prognosis of MDD. Positive social support may lead to recovery. Continuous onsets of stressors may worsen the symptoms. 

Thoughts of suicide and behaviour are major concerns in the mental health diseases MDD which can affect the prognosis. Any individual history of suicide attempt or persistent thoughts of suicide are the increased risk of recurrent episodes of MDD. 

Impaired cognitive functioning like memory and concentration difficulties may affect the prognosis. Substance abuse or dependency may complicate the prognosis of MDD and lead to the less positive results.  

Age group 

MDD can affect both children and adolescents. It manifests the symptoms like social withdrawal, changes in appetite, irritability, and performance decline. MDD is common in adults. 

It may affect the individuals from their adult life, from early to late adulthood. MDD can also affect the elder people. In this age group, the associated factors are like losing the loved one, chronic disease, and isolation from social life.  

MDD can affect people from any age. It may vary depending on the stage of development of MDD and life situations. 

Vital Signs: Measurement of blood pressure, pulse rate, body temperature, and respiratory rate 

Neurological Examination: Evolution of reflexes, coordination, muscular strength, and sensation 

Gastrointestinal System: Examination of changes in appetite and weight 

Medicine and Substance Use: Discussion of current medications use, including herbal supplements and substances used, including alcohol and drugs.  

Sleep Patterns: Discussion of sleep patterns and disturbances. 

Anxiety Disorders: MDD occurs with the various anxiety disease. The common symptoms of MDD and anxiety may result in a complex clinical significance. 

Substance Abuse: People with MDD may use the alcohol or drug in order to deal with the difficulties given by the symptoms of depression. This may lead to the substance use disease and it is important to address it to both the conditions. 

Suicidal Thoughts or behaviors: Chronic depression may increase the chances or risk of the suicide ideas and self-harm. It is necessary to give an individuals who suffer with MDD may get the necessary help and support from the mental healthcare providers. 

Eating Disorders: Conditions like bulimia nervosa, binge-eating disorder, and anorexia nervosa can occur with the MDD. These disease may involve the poor body image and unhealthy eating habits.  

Chronic Pain: MDD and chronic pain often occur together. Chronic pain diseases like arthritis or fibromyalgia may lead to development of MDD. It can increase the symptoms of pain.  

Sleep Disturbances: Many individuals who have MDD may have a disturbance in sleep patterns like hypersomnia or insomnia. These can lead to worse symptoms of depression. 

Social Isolation: MDD may also lead to the isolation from the social life. Isolation and absence from the social network may increase the chances of depression manifestation and hopelessness. 

Cognitive Impairment: MDD may affect the cognitive functions like attention, memory, and decision making. This can affect the ability of perform the daily activity.  

Reduced Physical Activity: People with MDD can experience the decrease in the physical activity level and lead to the sedative lifestyle. Lack of exercise may worsen the mental and physical health. 

Negative Impact on Relationships: MDD can also impact on the relationships with friends and family. The irritability and sadness which are linked to MDD can make the challenge to maintain the heathy relationships.  

Poor Academic or Occupational Performance: MDD can also lead to decreased performance in the academic and occupational. It decreases the motivation and concentration.  

Acute Onset: Symptoms of MDD may be severe and sudden and it is triggered by the life events, traumas or stress.  

Chronic or Persistent: Symptoms of MDD may develop over time, and it is triggered by the history of any low-level symptoms of depression. 

Severe Symptoms: The severe symptoms of MDD are suicidal thoughts, physical changes, intense feeling of despair, changes in weight, and changes in sleep pattens.  

Moderate Symptoms: The moderate symptoms of MDD are interference in daily life. Individual may experience the distress and impaired function, but it is not same as a severe symptoms.  

Atypical Symptoms: Some individuals may experience the atypical symptoms like increased sleep, leaden paralysis, and increased appetite. 

Recurrent Episodes: MDD can be recurrent disease with the acute symptoms episodes which are separated by the remission of periods.  

Initial Assessment and Diagnosis: 

Comprehensive evaluation and assessment carried out by a certified mental health expert to diagnose the MDD and elimination of the other possibility of the other medical or psychiatric diseases.  

Psychoeducation: Education to the patients and their families about the MDD, symptoms, and the treatment. 

Psychotherapy: 

Cognitive-Behavioral Therapy (CBT): This method is a systematic approach to recognize and change the detrimental effects of behavior and thought patterns which are contribute to the MDD.  

Psychodynamic Therapy: Investigation of the unconscious tension and prior life event may contribute to the MDD.  

Behavioral Activation: Encouragement of the active participation to the rewarding activities to help to withdraw and isolation to the depression.  

Mindfulness-Based Cognitive Therapy (MBCT): Combination of mindful method with CBT to prevent the MDD. 

Pharmacotherapy: 

Antidepressant Medications: antidepressant medications like SNRI, SSRI, norepinephrine reuptake inhibitors and certain class of drugs are used to treat the MDD. It depends on the severity and the type of depression. It is necessary to monitor the side effects and the therapeutic effects on patients.  

Adjunctive Medications: Adjunctive medications like atypical antipsychotics or mood stabilizers are used t treat the MDD in some cases. It is used specifically in the presence of symptoms of anxiety and mood instability. 

Medication treatment must include the close monitoring by a psychiatrist and regular assessment of effectiveness of medication and adverse side effects.  

Electroconvulsive Therapy (ECT): ECT is used in the severe or treatment resistant depression or for rapid relief from symptoms. Administration of general anesthesia is given by a specialized team. 

Lifestyle Modifications: Encouragement to change the routine life to an active physical life, balanced diet, sufficient rest, and stress relief methods.  

Supportive and Social Interventions: Engagement with the family, friends, and support groups.  

Continued Treatment: This includes the ongoing treatment or medications to prevent the recurrent of diseases.  

Regular Follow-up and Monitoring: Regular meetings and follow-ups from the mental healthcare providers to evaluate the effectiveness of treatment and progress.  

Alternative and Complementary Therapies: Some people may get the benefit of complementary therapies like meditation, yoga, acupuncture, or herbal supplements.  

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Create a Supportive Home Environment: Surround yourself with a supportive friends and family, keep organizing your living space, and decorate it with relaxing colors.  

Minimize Stressors: Recognize and removes the sources of stress, simplify your schedule, distribute work, and establish boundaries. 

Ensure Natural Light and Fresh Air: Make sure you living space gets adequate natural sunlight and open windows on regular basis.   

Establish a Physical Exercise Environment: Set a home exercise area or join gym and keep motivating elements in room. 

Promote Healthy Eating: Organize your kitchen for healthy eating and create a pleasant dining area. 

Limit Digital Overload: Reduce the exposure amount of negative content from social media or news and limit the screen time. 

The other lifestyle changes may involve the creation of mindful and relaxed areas, engagement in the creative activities, create a routine, create a social interaction space, incorporate yourself with nature and greenery,  

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Fluoxetine (Prozac): 

It has a long half-life and an oldest SSRIs. It stays in the body for a longer period of time than the other SSRIs. Fluoxetine acts as an inhibitor and it inhibits the reuptake of serotonin by neurons. It is suggested in many conditions which include the PTSD and social anxiety disease.  

Sertraline (Zoloft): 

Sertraline is prescribed to treat the MDD. It is also used to treat the various anxiety diseases.  

Paroxetine (Paxil): 

Paroxetine is used to treat the MDD and other conditions like generalized anxiety disease and panic disease. It acts in the brain channels that are imbalanced in the patients with anxiety, depression, or related diseases. It exhibits a low anticholinergic effects and induce the weight gain effect than the other SSRIs. 

Escitalopram (Lexapro): 

Escitalopram is a S-enantiomer of citalopram. It is more refined form of the citalopram. It is effective to treat the MDD. 

Citalopram (Celexa): 

Citalopram is an oldest SSRI. It is prescribing to treat MDD in some cases. Patients who have stable corrected QT interval level more than 500 ms should not take citalopram. 

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Venlafaxine (Effexor): 

Venlafaxine is primary treatment for MDD. It is used specifically in individuals with substantial fatigue or pain symptoms linked with the depression episode. Venlafaxine is used to treat the MDD and other various anxiety diseases. It comes with an immediate release and extended-release formulations. 

Duloxetine (Cymbalta): 

Duloxetine is used to treat the MDD, GAD, diabetic peripheral neuropathic pain, chronic musculoskeletal pain, and fibromyalgia. It is a primary treatment method to treat the substantial fatigue and pain symptoms along with the depression episode.  

Desvenlafaxine (Pristiq): 

Desvenlafaxine is closely associated with venlafaxine. It is an active antibodies of venlafaxine. It is used to treat the MDD and extended-release form of MDD.  

Levomilnacipran (Fetzima): 

Levomilnacipran is used to treat the MDD, and it is an option for patients who do not respond the other antidepressants. It is primary treatment option for patients to treat the substantial fatigue and pain symptoms along with the depression episode. 

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Amitriptyline is used to treat the depression, chronic pain, and migraine. It increases the serotonin and norepinephrine level within the brain. 

Imipramine: 

Imipramine I the first TCA developed. It is used to treat the MDD and various anxiety diseases. It affects the level of serotonin and norepinephrine.  

Clomipramine: 

Clomipramine is used to treat the OCD and depression. It has a selective action on serotonin uptake. 

Doxepin: 

Doxepin is used to treat the depression and sleep disease. It affects the level of serotonin and norepinephrine.  

Nortriptyline: 

Nortriptyline is a metabolite of amitriptyline. It is used to treat the MDD. It has mild side effects than the other TCAs.  

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Trazodone: 

Trazodone is antidepressant which is used to treat the depression. It is also prescribing for insomnia because of the sedative properties. It increases the serotonin level in brain by the inhibition of reuptake. It is often used in sleep problems as it helps to initiate and maintain the sleep. 

Vilazodone: 

Vilazodone is a new antidepressant. It is used to treat the MDD. It increases the level of serotonin in brain and modulate the serotonin receptor activity. 

Vortioxetine: 

Vortioxetine is another new antidepressant. It falls under the class of serotonin modulator and stimulator. It increases the level of serotonin and influences other neurotransmitter like serotonin receptors and norepinephrine. It is used in the cognitive symptoms. 

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Tranylcypromine: 

Tranylcypromine is an MAOI and is used to treat MDD. It is used when other antidepressants are not effective or not tolerable.  

Phenelzine: 

Phenelzine has a dietary restriction. Individuals must avoid the foods and drink which are high in tyramine. It is used to treat the depression in adults.  

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Psychotherapy: 

Initiation of individual therapy like Interpersonal Therapy (IPT), Mindfulness-Based Cognitive Therapy (MBCT), and Cognitive-Behavioral Therapy (CBT) based in the specific symptoms and need of patients.  

Encouragement of the regular participation to the therapy sessions to reduce the negative thoughts, emotional regulation, and interpersonal difficulties.  

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Assessment and Diagnosis: 

Accurate assessment by a healthcare provider is necessary to diagnose the MDD. Proper evaluation of symptoms, medical history, and underlying causes are important to treat MDD. 

Acute Phase: 

Immediate treatment is necessary to prevent the severe depression symptoms.  

Medication: Antidepressants medications like SSRI, SNRI, and other classes of antidepressants can be prescribed.  

Psychotherapy: Cognitive-behavioral therapy (CBT), interpersonal therapy (IPT), or other evidence-based therapies can be used. 

Hospitalization: In more extreme cases, hospitalization may become crucial especially when there is chance of self-harm or suicidal tendency.  

Continuation Phase: 

Once acute symptoms have been controlled then the treatment continues to prevent the recurrence. Medication and psychotherapy continue to address the underlying issues. Medication dosage is adjusted as per the need. Monitoring the side effects and assessing the treatment is necessary. 

Maintenance Phase: 

This phase is intended to prevent the additional episode of depression. Medications may be continued at a lower dosage. Psychotherapy may help the individuals to maintain the progression and resilience. Modify the activities like dietary choices, physical activity, and stress handling.  

Adjunctive Therapies: 

Electroconvulsive therapy (ECT): It is used in severe and treatment-resistant cases. 

Transcranial Magnetic Stimulation (TMS): It is an alternative method for treatment-resistant depression. 

Ketamine infusion therapy: It is an emerging treatment for severe depression. 

Support and Education: 

Education about the depression and management of it is necessary for patient and families. Emotional support is important to treat the depression. 

Regular Follow-up: 

Regular follow up with the healthcare providers is necessary to monitor the progress, emerging issues, and adjustment in treatment options. Adjustments in the medications is necessary over the time. 

Crisis Management and Holistic Self-Care 

Implementation of crisis plan to treat the severe relapse or suicidal thoughts. Understanding of when and how there is a need of immediate help. Encourage the patients to engage in self-care activities. Recognition and management of the relapse indicator and continues medications and therapy.