What Is The 4 Stage Of Depression?

Depression is a complex and often misunderstood mental illness that affects millions of individuals worldwide. In this article, we will explore the four different stages of depression and gain a deeper understanding of the progression of this condition. By shining a light on these stages, we hope to offer support, empathy, and ultimately, helpful insights for those who may be experiencing this daunting journey. So, let’s dive into the four stages of depression and discover the intricacies that lie within each one.

Stage 1: Mild Depression

Symptoms of mild depression

Mild depression, also known as dysthymia, is characterized by persistent feelings of sadness, low energy, and a general lack of interest or pleasure in activities. Some common symptoms of mild depression include:

  • Feelings of sadness or emptiness
  • Fatigue and low energy levels
  • Changes in appetite and weight
  • Sleep disturbances, either insomnia or excessive sleep
  • Difficulty concentrating or making decisions
  • Feelings of hopelessness or worthlessness
  • Loss of interest in activities once enjoyed
  • Irritability or restlessness

These symptoms may not be severe enough to significantly impact daily functioning, but they can still cause distress and affect overall well-being.

Causes of mild depression

The exact causes of mild depression are not fully understood, but it is likely a combination of genetic, biological, environmental, and psychological factors. Some potential causes or risk factors for mild depression include:

  • Family history of depression
  • Imbalances in brain chemicals, such as serotonin and dopamine
  • Chronic medical conditions, such as diabetes or heart disease
  • Stressful life events or major life changes
  • Childhood trauma or abuse
  • Certain personality traits, such as perfectionism or low self-esteem
  • Social isolation or lack of support

It is important to note that everyone’s experience with depression is unique, and the causes can vary from person to person.

Treatment options for mild depression

The treatment options for mild depression generally focus on a combination of medication, therapy, and lifestyle changes. Some common treatment approaches for mild depression include:

  • Antidepressant medication: Selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs) may be prescribed to help balance brain chemicals associated with mood regulation.
  • Therapy: Cognitive-behavioral therapy (CBT), interpersonal therapy (IPT), or other forms of talk therapy can help individuals identify and change negative thought patterns and behaviors contributing to depression.
  • Lifestyle changes: Engaging in regular exercise, maintaining a balanced diet, getting enough sleep, and practicing stress management techniques like meditation or relaxation exercises can all have a positive impact on mood.
  • Social support: Connecting with friends, family, or support groups can provide a sense of community and reduce feelings of isolation.
  • Self-care: Engaging in activities that bring joy or relaxation, practicing self-compassion, and setting realistic goals can all contribute to overall well-being.

If left untreated, mild depression can progress to more severe forms. It is important to seek professional help if you are experiencing persistent symptoms of depression.

Stage 2: Moderate Depression

Symptoms of moderate depression

Moderate depression is characterized by more pronounced and disabling symptoms compared to mild depression. Some common symptoms of moderate depression include:

  • Persistent feelings of sadness, hopelessness, or despair
  • Loss of interest or pleasure in almost all activities
  • Significant changes in appetite and weight
  • Insomnia or hypersomnia (excessive sleep)
  • Fatigue and a lack of energy
  • Difficulty concentrating or making decisions
  • Feelings of worthlessness or excessive guilt
  • Agitation or psychomotor retardation (slowed movements and thoughts)
  • Recurrent thoughts of death or suicide

Moderate depression can significantly impact daily functioning and may interfere with work, school, and relationships.

Causes of moderate depression

Similar to mild depression, the causes of moderate depression can be multifactorial. Some potential causes or risk factors for moderate depression include:

  • A history of previous depressive episodes
  • Chronic stress or ongoing life difficulties
  • Substance abuse or dependence
  • Relationship problems or social isolation
  • Physical health problems, such as chronic pain or a serious illness
  • Hormonal imbalances, such as those occurring during pregnancy or menopause
  • Family history of depression or other mental health disorders

It is important to recognize that the causes can vary from person to person, and there may be multiple factors contributing to the development of moderate depression.

Treatment options for moderate depression

Treating moderate depression often involves a combination of medication, therapy, and lifestyle changes. Some common treatment options for moderate depression include:

  • Antidepressant medication: SSRIs, SNRIs, or other classes of antidepressants may be prescribed to help alleviate symptoms and improve mood.
  • Psychotherapy: Different types of therapy, such as CBT, IPT, or psychodynamic therapy, can help individuals explore underlying issues, develop coping strategies, and promote emotional well-being.
  • Hospitalization or intensive outpatient programs: In severe cases or when safety concerns arise, hospitalization or intensive treatment programs may be necessary to provide round-the-clock care and support.
  • Lifestyle changes: Engaging in regular physical activity, maintaining a structured routine, and incorporating relaxation techniques or stress management strategies can all help improve mood and overall well-being.
  • Social support and self-care: Building a strong support system, participating in meaningful activities, and practicing self-care are crucial for individuals with moderate depression to ensure they receive the necessary support and promote recovery.

Seeking professional help is essential for those experiencing moderate depression, as early intervention can prevent the condition from worsening.

Stage 3: Severe Depression

Symptoms of severe depression

Severe depression, also known as major depressive disorder (MDD), is a serious mental health condition that can significantly impact all areas of life. Symptoms of severe depression include:

  • Overwhelming feelings of sadness, despair, or emptiness
  • Profound loss of interest or pleasure in almost all activities
  • Unintentional weight loss or gain
  • Insomnia or hypersomnia nearly every day
  • Extreme fatigue and loss of energy
  • Difficulty concentrating, thinking, or making decisions
  • Feelings of worthlessness, guilt, or self-hatred
  • Psychomotor agitation or retardation
  • Recurrent thoughts of death or suicide, suicide attempts

Individuals with severe depression often experience impairment in their ability to function in daily life, and symptoms may be persistent and severe.

Causes of severe depression

The causes of severe depression are complex and can be influenced by various biological, genetic, psychological, and environmental factors. Some potential causes or risk factors for severe depression include:

  • A history of recurrent depressive episodes
  • Family history of depression or other mental health conditions
  • Certain medical conditions, such as thyroid disorders or cancer
  • Substance abuse or addiction
  • Chronic stress or traumatic life events
  • Personal or family history of trauma or abuse
  • Neurotransmitter imbalances in the brain, such as decreased levels of serotonin or norepinephrine

It is vital to recognize that severe depression is a legitimate medical condition and is not solely related to personal weakness or a lack of willpower.

Treatment options for severe depression

The treatment approach for severe depression often involves a combination of medication, therapy, and other interventions. Key treatment options for severe depression may include:

  • Antidepressant medication: Depending on individual factors, different classes of antidepressants, such as SSRIs, SNRIs, or tricyclic antidepressants, may be prescribed to help balance brain chemicals and reduce symptoms.
  • Psychotherapy: Intensive therapy, such as CBT or psychoanalytic therapy, can help individuals explore the underlying causes of their depression, develop coping strategies, and establish healthier patterns of thinking and behavior.
  • Electroconvulsive therapy (ECT): In severe cases or when other treatments have been ineffective, ECT may be recommended to stimulate the brain using electrical currents and alleviate symptoms.
  • Transcranial magnetic stimulation (TMS): This non-invasive procedure involves using magnetic fields to stimulate specific regions of the brain associated with mood regulation.
  • Hospitalization or residential treatment: In cases of severe depression that pose a risk to the individual’s safety or when symptoms are particularly debilitating, inpatient or residential treatment programs can provide intensive care and support.
  • Complementary and alternative treatments: Some individuals may find benefit from activities like exercise, mindfulness meditation, acupuncture, or herbal supplements. However, it is crucial to consult with healthcare professionals before trying any alternative treatments.

The treatment of severe depression requires a comprehensive and individualized approach to address both the biological and psychological aspects of the condition.

Stage 4: Major Depressive Disorder (MDD)

Symptoms of major depressive disorder

Major depressive disorder (MDD) is a severe form of depression characterized by the presence of at least five specific symptoms over a two-week period. These symptoms must significantly impair daily functioning and represent a change from previous functioning. Some key symptoms of MDD include:

  • Depressed mood most of the day, nearly every day
  • Loss of interest or pleasure in almost all activities
  • Significant weight loss or gain, or changes in appetite
  • Insomnia or hypersomnia on a daily basis
  • Psychomotor agitation or retardation nearly every day
  • Fatigue or loss of energy
  • Feelings of worthlessness or excessive guilt
  • Difficulty concentrating, making decisions, or thinking clearly
  • Recurrent thoughts of death or suicide

To receive a diagnosis of MDD, symptoms must cause significant distress or impair occupational, social, or other important areas of functioning.

Causes of major depressive disorder

The exact causes of major depressive disorder are not fully understood, but it is believed to be the result of a complex interplay between genetic, biological, environmental, and psychological factors. Some potential causes or risk factors for major depressive disorder include:

  • Family history of depression or other mental health conditions
  • Chemical imbalances in the brain, including disruptions in the regulation of neurotransmitters like serotonin, norepinephrine, and dopamine
  • Significant life stressors, such as trauma, loss, or abuse
  • Chronic medical conditions, such as heart disease, cancer, or autoimmune disorders
  • Hormonal changes, such as those occurring during pregnancy or menopause
  • Substance abuse or addiction
  • Sociocultural factors, such as socioeconomic disadvantage or discrimination

It is important to note that while these factors may increase the risk of developing MDD, having one or more of these factors does not guarantee the development of major depressive disorder.

Diagnosis and classification of major depressive disorder

The diagnosis of major depressive disorder involves a comprehensive evaluation by a healthcare professional, usually a psychiatrist or psychologist. They will assess an individual’s symptoms, their duration and severity, and the impact on daily functioning. The diagnostic process may involve:

  • Clinical interview: The healthcare professional will gather information about the individual’s symptoms, medical history, and any family history of mental health conditions.
  • Diagnostic criteria: The healthcare professional will refer to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, which outlines the specific symptoms and duration required for a diagnosis of major depressive disorder.
  • Screening tools: Specialized questionnaires or rating scales, such as the Beck Depression Inventory (BDI) or the Patient Health Questionnaire-9 (PHQ-9), may be used to help assess the severity of depressive symptoms and guide treatment planning.

It is crucial to receive an accurate diagnosis to ensure appropriate treatment and support.

Treatment options for major depressive disorder

The treatment approach for major depressive disorder typically involves a combination of medication, therapy, and other interventions. Some common treatment options for major depressive disorder include:

  • Antidepressant medication: Different classes of antidepressants may be prescribed based on individual factors, including the severity of symptoms, previous treatment responses, and potential side effects.
  • Psychotherapy: Various therapeutic modalities, such as CBT, IPT, or psychodynamic therapy, can help individuals develop coping strategies, challenge negative thought patterns, and improve overall well-being.
  • Electroconvulsive therapy (ECT): In severe cases or when other treatments have been ineffective, ECT may be recommended to induce controlled seizures and influence brain chemistry.
  • Transcranial magnetic stimulation (TMS): This non-invasive procedure uses magnetic fields to stimulate specific areas of the brain associated with mood regulation.
  • Hospitalization or residential treatment: In cases of severe depression with suicidal thoughts, severe impairment, or an inability to function, hospitalization or residential treatment may be necessary to provide intensive care and safety monitoring.
  • Adjunctive therapies: Supportive therapies like art therapy, music therapy, or exercise programs may also be beneficial for individuals with major depressive disorder.

Treatment for major depressive disorder requires ongoing management and monitoring to ensure optimal response and recovery. It is essential for individuals to work closely with healthcare professionals to develop a personalized treatment plan.

Differentiating between stages of depression

Clinical assessments and criteria

Differentiating between stages of depression requires careful clinical assessment and consideration of various diagnostic criteria. Healthcare professionals typically use standardized diagnostic criteria, such as those outlined in the DSM-5, to aid in the diagnosis and classification of depression. These criteria specify the required number and duration of symptoms needed for each stage of depression.

Healthcare professionals may also use clinical interviews, questionnaires, and rating scales to gather information about an individual’s symptoms, severity, and functional impairment. These assessments provide valuable insights and help determine the appropriate treatment approach.

Severity scales and measurement tools

To assess the severity of depression, healthcare professionals may use severity scales and measurement tools, such as the Hamilton Depression Rating Scale (HDRS) or the Montgomery-Ã…sberg Depression Rating Scale (MADRS). These scales help quantify depression symptoms and track changes in severity over time.

Severity scales typically rate various symptoms, such as depressed mood, feelings of guilt, insomnia, and changes in appetite, on a numerical scale. The total score provides an indication of the severity of depression.

By using these clinical assessments and severity scales, healthcare professionals can better differentiate between the stages of depression and tailor treatment plans accordingly.

Comorbidity and complicating factors

Additional mental health conditions

Depression often co-occurs with other mental health conditions, leading to comorbidity. Some common mental health conditions that may coexist with depression include:

  • Anxiety disorders: Conditions such as generalized anxiety disorder, panic disorder, or social anxiety disorder are frequently seen alongside depression.
  • Substance use disorders: Depression is closely linked to substance abuse and addiction, as individuals may turn to substances as a way to cope with or self-medicate their symptoms.
  • Eating disorders: Conditions like anorexia nervosa, bulimia nervosa, or binge eating disorder frequently coexist with depression, as they often stem from similar underlying emotional and psychological factors.
  • Attention-deficit/hyperactivity disorder (ADHD): Individuals with ADHD are at an increased risk of developing depression due to difficulties with concentration, impulsivity, and emotional regulation.
  • Post-traumatic stress disorder (PTSD): Traumatic experiences can trigger both depression and PTSD, as well as exacerbate symptoms of existing depression.

Individuals with comorbid conditions often face more complex treatment challenges, requiring a multidimensional approach to address all aspects of their mental health.

Physical health conditions

Depression can also coexist with various physical health conditions, further complicating the management and treatment process. Some examples of physical health conditions commonly associated with depression include:

  • Cardiovascular diseases: Depression is often found in individuals with heart disease, stroke, or other cardiovascular conditions, possibly due to shared risk factors and inflammatory processes.
  • Chronic pain conditions: Conditions like fibromyalgia, migraines, or arthritis can lead to depression due to the impact of persistent pain on physical and emotional well-being.
  • Cancer: A cancer diagnosis can significantly impact an individual’s mental health, leading to depression or exacerbating existing depressive symptoms.
  • Diabetes: Managing a chronic condition like diabetes can be emotionally challenging, and individuals with diabetes have an increased risk of developing depression.
  • Neurological disorders: Depression is frequently found in individuals with neurological conditions such as Parkinson’s disease, multiple sclerosis, or epilepsy.

It is crucial to address both the physical and mental health aspects when managing comorbidities, as treating underlying physical health conditions can help improve depressive symptoms.

Substance abuse and addiction

Depression and substance abuse often occur together, creating a complex and challenging situation for individuals. Substance abuse can be both a cause and consequence of depression, as individuals may use drugs or alcohol as a way to self-medicate their depressive symptoms. However, substance abuse can also exacerbate or trigger depressive episodes.

The coexistence of depression and substance abuse requires a comprehensive treatment approach that addresses both conditions simultaneously. This may involve detoxification, rehabilitation programs, counseling, and ongoing support to address the underlying issues contributing to both disorders.

Misdiagnosis and overlapping symptoms

Challenges in accurately diagnosing depression stages

Accurately diagnosing the stages of depression can be challenging due to several factors, including overlapping symptoms with other mental health conditions and the subjective nature of self-reporting symptoms. Challenges in diagnosing depression stages may include:

  • Patient disclosure: Individuals with depression may underreport or minimize their symptoms due to feelings of shame, fear, or a lack of insight into their condition.
  • Overlapping symptoms: Symptoms such as fatigue, changes in appetite, or sleep disturbances can be present in various mental health disorders, making it difficult to differentiate between them solely based on symptoms.
  • Coexisting mental health conditions: The presence of comorbid conditions, such as anxiety or substance use disorders, can further complicate the diagnosis and classification of depression stages.
  • Diagnostic criteria interpretation: Healthcare professionals may interpret diagnostic criteria differently, leading to variations in the diagnosis and categorization of depression stages.

To minimize the risk of misdiagnosis and ensure accurate treatment, it is crucial to consult with experienced healthcare professionals who specialize in mental health.

Distinguishing depression from other mental disorders

Differentiating depression from other mental disorders can be challenging, as symptoms can overlap across various conditions. Some mental health disorders that may present with symptoms resembling depression include:

  • Bipolar disorder: Bipolar disorder involves periods of depressive episodes alternating with periods of mania or hypomania. Distinguishing between depressive episodes in bipolar disorder and major depressive disorder can be challenging, as the symptoms may appear similar.
  • Anxiety disorders: Certain anxiety disorders, such as generalized anxiety disorder or panic disorder, can cause symptoms like sleep disturbances, irritability, and changes in appetite, which are commonly associated with depression.
  • Adjustment disorder: Individuals experiencing significant life stressors or major life changes may develop adjustment disorder, which can manifest with symptoms resembling depression and anxiety.
  • Borderline personality disorder: This personality disorder can present with intense mood swings, feelings of emptiness, self-destructive behaviors, and relationship difficulties, which can overlap with symptoms of depression.

To accurately diagnose and differentiate between these conditions, comprehensive clinical evaluations, diagnostic interviews, and consideration of the individual’s full symptom profile are necessary.

Progression and prognosis

Natural course of depression

The natural course of depression can vary widely depending on factors such as individual characteristics, treatment interventions, and the presence of comorbid conditions. For some individuals, depression may follow a chronic course, with recurrent episodes lasting several months or longer. Others may experience a more episodic pattern, with periods of remission between episodes.

The duration and severity of depressive episodes can also differ significantly. Mild or moderate depression may resolve with appropriate treatment and support, while severe depression or major depressive disorder often requires ongoing management and treatment to prevent relapse.

Factors that influence the progression

Several factors can influence the progression and course of depression:

  • Treatment adherence: Consistent engagement in treatment, including medication adherence and therapy attendance, can significantly impact the course of depression and reduce the risk of relapse.
  • Lifestyle factors: Engaging in healthy lifestyle habits, such as regular exercise, maintaining a balanced diet, and managing stress, can help improve mood and overall well-being, potentially influencing the progression of depression.
  • Social support: Having a strong support system and access to social support networks can play a vital role in recovery and prevent isolation, which can exacerbate depressive symptoms.
  • Comorbid conditions: The presence of comorbid mental health or physical health conditions can complicate the progression of depression and influence treatment outcomes.
  • Early intervention: Receiving early intervention and appropriate treatment for depression can minimize the severity and duration of symptoms, potentially preventing the progression to more severe stages.

It is important to recognize that the course of depression is highly individual, and the prognosis can vary based on these and other factors.

Long-term prognosis and recovery

With proper treatment and support, many individuals with depression can experience significant improvements in symptoms and achieve long-term recovery. However, the long-term prognosis for depression can depend on several factors, including:

  • Treatment response: The effectiveness of treatment interventions, including medication and therapy, can significantly impact the long-term prognosis of depression. Some individuals may require multiple treatment attempts or adjustments to find an approach that works best for them.
  • Coexisting conditions: The presence of comorbid mental health or physical health conditions can complicate treatment and influence prognosis. Addressing these conditions in conjunction with depression is crucial for long-term recovery.
  • Recurrence and relapse prevention: Individuals with depression may experience recurrent episodes or relapses following periods of remission. Developing relapse prevention strategies and engaging in ongoing treatment and support can help reduce the risk of relapse.
  • Personal resilience: Individual factors, such as a strong support system, effective coping mechanisms, positive self-care practices, and a healthy lifestyle, can contribute to long-term recovery and resilience in the face of future challenges.

It is important for individuals with depression to stay connected to their support networks, engage in ongoing treatment, and communicate openly with healthcare professionals to optimize their long-term prognosis and recovery.

Prevention and early intervention

Risk factors for developing depression

While the exact cause of depression is not fully understood, certain risk factors can increase an individual’s susceptibility to developing the condition. Some common risk factors for depression include:

  • Family history: Having a family history of depression or other mental health conditions can increase the risk of developing depression.
  • Personal history: Individuals who have previously experienced depressive episodes are more likely to experience future episodes.
  • Early-life experiences: Adverse childhood experiences, such as abuse, neglect, or early loss, can increase the risk of depression later in life.
  • Chronic stress: Persistent stressors, such as financial difficulties, relationship problems, or work-related stress, can contribute to the development of depression.
  • Social isolation: A lack of social support or connection can increase the risk of developing depression.
  • Gender: Females are more likely than males to experience depression, although the reasons for this disparity are not fully understood.

While these risk factors can increase the likelihood of developing depression, it is important to note that not everyone with these risk factors will develop the condition. The interplay of genetic, biological, and environmental factors is complex and multifactorial.

Identifying early signs and symptoms

Early identification of depression is crucial for timely intervention and prevention of the progression to more severe stages. Some early signs and symptoms of depression may include:

  • Persistent sadness or low mood
  • Loss of interest or pleasure in activities
  • Changes in appetite or weight
  • Sleep disturbances, such as insomnia or excessive sleep
  • Fatigue or loss of energy
  • Difficulty concentrating or making decisions
  • Feelings of worthlessness or excessive guilt
  • Irritability or restlessness
  • Thoughts of death or suicide

If you or someone you know is experiencing these symptoms for more than two weeks or if these symptoms significantly impact daily functioning, it is important to seek professional help for an accurate diagnosis and appropriate treatment.

Effective prevention strategies

While it may not be possible to completely prevent depression, several strategies can help reduce the risk or delay the onset of the condition. Here are some effective prevention strategies:

  • Social support: Building and maintaining strong social connections can provide a buffer against depression. Joining support groups, participating in community activities, or nurturing relationships with friends and family can promote emotional well-being.
  • Stress management: Developing healthy coping mechanisms, such as regular exercise, relaxation techniques, or practicing mindfulness, can help manage stress and reduce the risk of developing depression.
  • Healthy lifestyle habits: Engaging in regular physical activity, maintaining a balanced diet, getting enough sleep, and avoiding excessive alcohol or substance use can contribute to overall well-being and reduce the risk of depression.
  • Early intervention: Seeking help at the first signs of depression or emotional distress can prevent the condition from worsening. Prompt treatment, whether through therapy, medication, or a combination of approaches, can significantly improve outcomes and prevent the progression to more severe stages.
  • Education and awareness: Increasing awareness of the signs and symptoms of depression, reducing stigma surrounding mental health, and promoting help-seeking behaviors can all contribute to early intervention and prevention.

If you are concerned about your risk of developing depression, it is important to discuss your concerns with a healthcare professional who can provide guidance and support.

Support and resources

Professional help and therapy

Seeking professional help is crucial for individuals experiencing depression at any stage. Mental health professionals, such as psychiatrists, psychologists, or licensed therapists, can provide support, evaluate the severity of symptoms, and recommend appropriate treatment options. Therapy can offer a safe space to explore and address underlying issues, develop coping skills, and promote emotional well-being.

  • Psychiatrists: Medical doctors specializing in diagnosing and treating mental health conditions, including depression. They can prescribe medication and provide ongoing monitoring.
  • Psychologists: Mental health professionals trained in therapy techniques to help individuals address emotional and psychological challenges, including depression.
  • Licensed therapists: Therapists, such as licensed clinical social workers or licensed professional counselors, can provide counseling and support for individuals with depression.

An initial step may involve contacting your primary care physician, who can provide referrals to mental health professionals or recommend appropriate resources.

Support groups and peer networks

Support groups can offer valuable connections and emotional support for individuals with depression. These groups provide a safe space to share experiences, learn coping strategies, and receive peer support. Support groups for depression can be found locally, through mental health organizations or community centers, or online via forums and virtual platforms.

Peer networks, such as online communities or social media groups, can also provide a sense of camaraderie and understanding. Engaging with others who have gone through similar experiences can reduce feelings of isolation and offer insights into coping with depression.

Online resources and helplines

There are numerous online resources and helplines available to provide information, support, and crisis intervention for individuals experiencing depression. Here are some reputable resources:

  • National Suicide Prevention Lifeline: 1-800-273-TALK (1-800-273-8255)
  • Crisis Text Line: Text “HELLO” to 741741 in the United States
  • National Alliance on Mental Illness (NAMI): NAMI provides education, resources, and support groups for individuals and families affected by mental illness.
  • Depression and Bipolar Support Alliance (DBSA): DBSA offers online resources, support groups, and educational materials for individuals with depression and bipolar disorder.

These resources can be valuable sources of information, support, and guidance for individuals seeking help or wanting to learn more about depression.

In summary, depression can manifest in different stages, ranging from mild to severe. Understanding the symptoms, causes, and treatment options for each stage is essential for identifying and managing the condition effectively. Seeking professional help, engaging in therapy, building social support networks, and practicing self-care are critical steps in both prevention and recovery. Remember, you are not alone, and support is available to help you navigate through the challenges of depression.