Depression is a life-threatening condition characterized by a neurometabolic disorder in the brain. Cuijpers define depression as a mental disorder characterized by persistent low mood. Clinical studies have revealed that different aspects of human physiology including hippocampal neurogenesis, neurotropic factors, neuropeptide factors and neurotransmitters change in individuals suffering from depression. Depressive disorders are widespread and closely associated with substantial economic costs, considerable disease burden and a significant worsening of the quality of life. According to Johansson, Lundh, and Bjarehed, approximately 5% of the world population suffer from depression at any given time. Epidemiological studies have reported that 10-20% of the population globally experiences depression at some point in their life with the highest incidence during adulthood. The study conducted by the World Health Organization (WHO), revealed that by 2020, depression would have been among the three leading causes of disability worldwide. In 2010, depression affected approximately 300 million people worldwide. The United States national institutes of mental health estimated that major depressive disorders affect 20 million individuals annually in the US alone. Depression is characterized by a wide range of symptoms including fatigue, feeling of worthlessness, insomnia, irritability, eating disorders, persistent sadness and continuous pain. The purpose of the current research paper is to investigate the causes of depression, its effects on one’s quality of life, effective treatment measures, and co-occurring disorders.
Causes of Depression
There is no single cause of depression, but there are potential factors including genetic, physical and environmental factors. Environmental factors such as significant life stressors, lack of a sufficient social life, trauma and negative life events contribute to the development of depression. The complex interaction of the environment and brain function leads to depression. Depression is a genetic disorder and individuals whose family member suffers from the disorder are at a higher risk of developing this disease as compared to people without a family history. Depressive disorders have a relation to multiple genes, and thus people without a family history can also be diagnosed with the disease.
Depression also has a relation to neurotransmitters. Chemical imbalance causes depression. Several brain chemicals such as dopamine and serotonin are involved in mood regulation and play a significant role in the development of depression. Imbalance in dopamine and serotonin leads to depression due to the inability of a person to feel good. Additionally, changes in the function of the brain chemicals and their interaction with neurocircuits that are involved in the regulation of mood play a crucial role in the onset of depression and designing treatment.
Neuroimaging studies have revealed that differences in the shape and size of the brain regions are responsible for appetite and mood. Three brain structures, namely the prefrontal cortex, amygdala, and hippocampus help the brain determine stressful situations and how to respond to them. Impairment of the brain structure such as brain tumors and head injuries can cause damage to the physical composition of the brain resulting in depression. However, it remains unknown whether changes in brain structure are the cause of the effect of depression.
Effects of Depression
Depression has a negative impact on individual’s quality of life. According to Cuijpers, depression significantly impairs certain areas including health, social functioning, and work functioning. Among the elderly, depression is a disabling condition that negatively influences the quality of life and increases the risk of mortality. If left untreated, depression can affect individual’s performances at school or work and disrupt the normal activities. People suffering from depression also experience loss of appetite and weight. There is also a disruption of the sleeping patterns as an individual may experience difficulties falling asleep or may sleep more often. A decreased physical activity and general loss of energy are also some of the effects of depression. Furthermore, a feeling of guilt and worthlessness may be present which may lead to recurring thoughts of suicide or attempts to commit suicide.
Treatment of Depression
Several efficacious treatment measures for depression are available. Until recently depression has been treated with the use of insight-oriented therapy, medications or a combination of both means of treatment. Notable advances in the treatment of depression have emerged in the past three decades including new psychological treatment and anti-depressants. These new treatment approaches suggest a different etiological model for depression. According to Johansson, anti-depressant medications and psychotherapy are the most efficacious means of treatment for depressive disorders.
Anti-depressant medications are helpful in mitigating the symptoms associated with depression particularly in mild to moderate cases of depression. There are three types of anti-depressant drugs: selective serotonin reuptake inhibitors, monoamine oxidase inhibitors and tricyclic anti-depressants. Monoamine oxidase works by repressing the activity of certain neurotransmitters in the brain. These drugs have been found to be ineffective, and thus they are used when all the other anti-depressants have failed. Tricyclic drugs are effective in removing acute depression symptoms. They relieve depression by inhibiting synaptic uptake of serotonin and norepinephrine but also affect other neurochemical systems such as cholinergic and histaminergic systems. Physical dependence and tolerance do not occur in the case of tricyclic anti-depressants, and they are more efficient than other anti-depressant drugs. Selective serotonin reuptake inhibitors relieve depression by inhibiting serotonin reuptake in presynaptic membranes.
The mode of action of antidepressants involves the neurotransmitters in the brain. Antidepressant therapy derives changes in both postsynaptic and presynaptic neurotransmitters decreasing the sensitivity at the presynaptic sites while increasing the sensitivity at the postsynaptic sites, which is an activity that corrects the abnormal relationship between receptors and neurotransmitters mitigating the symptoms of depression. An antidepressant may also work by realigning the connection between the limbic and cortical areas of the brain. Patients suffering from depression have an unusual relationship between these two brain areas. Treatment with the use of antidepressant drugs increases the connection between these regions and is associated with a regulatory influence of the cortical mood-regulating regions on the limbic areas of the brain.
Psychotherapy is useful for treating depression and relieving the symptoms experienced by an individual who suffers from the disorder. Many approve it as the first-line treatment of mild, moderate and severe depression. There are various approaches to psychotherapy including interpersonal and cognitive-behavioral therapy. Psychotherapy enables an individual with the disorder to understand and identify the causes of their depression and effectively address their interpersonal, behavioral, situational and psychological contributors. According to Cuijpers psychotherapy is more effective than antidepressant medications in preventing relapses. However, in some patients a combination of psychotherapy and anti-depressant medications is more effective than the alternative treatment on its own. Psychotherapy and antidepressants work differently. Therefore, a combination of these treatment measures is more effective than either of them used alone. The combined treatment has some benefits. The main kinds of psychotherapy that have proven to be efficacious in the treatment of depression include psychodynamic psychotherapy, cognitive behavioral therapy (CBT) and interpersonal psychotherapy.
Cognitive Behavioral Therapy (CBT)
CBT as a structured psychological means of treatment recognizes that both cognition and behavioral aspects affect people's thoughts, feelings and mood. It perceives depression as an effective response to negative beliefs and thus focuses on modifying the unproductive beliefs. CBT for depressive behavior includes interventions that focus on dysfunctional automatic thoughts, observable behaviors, and the underlying cognitive structures. CBT aims at helping the individual to recognize negative patterns of behavior and replace them with healthy thinking. Treatment is carried out in a continuous manner, focusing on cognitive restructuring and behavioral activation. In cognitive restructuring, the therapist assists the client to change the pattern of thinking through structured learning experiences that assist patients in monitoring their thoughts. In behavioral activation patients are shown how to overcome obstacles to participating in productive and enjoyable activities. Therapists start treatment by focusing on overt behaviors, educating patients on how to assess their attitude, corrective distortions in thinking and then identification and modification of more stable cognitive structures and depressive schemas.
Cognitive-behavioral therapy is the most common type of psychotherapeutic treatment. It is effective for patients of different age groups including adults, adolescents, and children. Recently, new models for cognitive behavioral therapy have emerged including metacognitive and transdiagnostic approaches. It is more efficient in producing remission as compared to non-specific psychotherapy or no treatment. The combination of cognitive behavioral therapy and antidepressant drugs increases adherence.
Interpersonal Psychotherapy (IP)
Interpersonal psychotherapy focuses on interpersonal issues and treatment alliance where therapists engage with patients and help them feel understood. Its target includes increasing social support, improving interpersonal functioning and symptom resolution. IP relies on the concept that there is a strong correlation between psychological symptoms associated with depression and interpersonal distress. It attempts to link painful life events that trigger or follow the development of the disorder and changes in the patient's mood. According to Cuijpers, interpersonal psychotherapy attempts to identify and track disturbing changes in individual and interpersonal environments such as role dispute, complicated bereavement, and other disturbing life upheavals. Symptoms of depression include distorted interpersonal functioning leading to serious consequences. The role of clients in interpersonal psychotherapy is to assist the patient to deal with difficult life events and build a social life. Interpersonal psychotherapy holds that addressing challenging life events alleviates depressive symptoms.
Psychodynamic psychotherapy refers to a wide range of treatments that involve psychoanalytic concepts. During this kind of treatment, the analyst seeks to follow the patient and understand the unique process set by personal difficulties, anxieties, occupation, character and way of building relations. It revolves around the idea that everyone experiences some internal states that are always difficult to deal with and understand. Psychoanalysis provides a thorough familiarity with these internal states. Psychoanalytic changes occur gradually, while the cognitive and emotional development involved in the treatment focuses on learning by internalizing rather than memorizing. Analysts conduct training and share their knowledge of identity and challenge to deal with patients' difficulties. As a result of such treatment, an individual slowly develops the capacity to cope with the pressures.
Some disorders occur along with depression. Depression co-occurs with anxiety disorders, panic disorder, obsessive-compulsive disorder, borderline personality disorder, substance abuse, alcoholism and the eating disorders. Depression, panic disorder, and anxiety disorders co-exist. Approximately 33% of people diagnosed with depression suffer from panic attacks during their depressive episodes. About 85% of individuals suffering from major depression have serious anxiety symptoms. Borderline personality disorder is highly comorbid with depression, and these two disorders share many biological characteristics. Borderline personality disorder co-occurs with depression. Depression triggers substance and alcohol abuse. Depression often occurs along with the obsessive compulsive disorder which explains the reason why psychotherapy is the preferred kind of treatment. People suffering from depression have a tendency to resort to drug and alcohol abuse to feel better.
Depression is a prevalent disease yet treatable. It arises from multiple factors including environmental, genetic and physical ones as well as changes in the brain function and structure. Treatment of depression has evolved and currently includes anti-depressant drugs and psychotherapies. Anti-depressant drugs influence the neurotransmitters in the brain whereas psychotherapies treat depression by assisting patients to understand the causes of their disorder and training them on how to cope with challenging life events. The different mechanisms of these two treatment approaches suggest that a combination of treatment measures is more effective that either of them alone.