Understanding Subsyndromal Depression : Symptoms, Causes, and Treatment Options

1. What is Subsyndromal Depression?

   Subsyndromal depression is a clinical condition characterized by depressive symptoms that do not meet the full criteria for major depressive episodes as outlined by the Diagnostic and Statistical Manual of Mental Disorders.

   Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR) is used for standard classification of mental health conditions.⁽¹⁾ If a person has 2 or more symptoms of depression present for most of the time for at least 2 or more months, he can be diagnosed with subsyndromal depression.
   

2. Prevalence and Significance of Subsyndromal Depression

   Subsyndromal depression is a common mental health condition. It is observed that 5-20% of the general population may experience depressive symptoms at any given time. The prevalence rate increases in individuals with chronic medical conditions, older adults, and those with a history of major depressive disorders.

   Females are at a higher risk of major depressive disorder.

   Even if subsyndromal depression does not meet the criteria for major depressive disorder, it has a few significant key points:

   • Impaired Functioning: There can be significant impairment in various areas of life including work or academic performance, interpersonal relationships, and overall quality of life. Even if the symptoms are less severe as compared to major depressive disorder, they can have a noticeable impact on daily functioning and well-being.
   • Increased Risk of Major Depressive Disorder: Subsyndromal depression is associated with an elevated risk of major depressive disorder.⁽²⁾ Early identification and intervention of subsyndromal depression may be helpful in preventing the onset of major depressive disorder.
   • Mental Health Burden: Subsyndromal depression can contribute to the burden of mental health conditions in society. This can increase healthcare utilization, decrease productivity and elevate the cost of healthcare services. Addressing subsyndromal depression can have an implication for public health and resource allocation.
   • Individual Distress: Subsyndromal depression can cause significant distress and suffering for those experiencing it. The symptoms can be milder and can have a negative impact on emotional well-being, self-esteem, and overall mental health.
   • Treatment Opportunities: Identification of subsyndromal depression provides opportunities for early intervention and support. Addressing the symptoms may be helpful in developing coping strategies, accessing appropriate treatment, and preventing further deterioration in mental health.

The symptoms of subsyndromal depression are similar to those of major depressive disorder but are less severe and of shorter duration.

The common symptoms include: 

• Emotional Symptoms: These include persistent feelings of sadness, emptiness, or hopelessness. There is a loss of interest in previously enjoyed activities with increased irritability and frustration. The person is sensitive emotionally and is easily triggered. There is a decrease in self-esteem or feelings of worthlessness.
• Cognitive Symptoms: The person feels difficulty in concentrating, making decisions, and remembering things. There are negative thinking patterns, including self-criticism, and excessive guilt. There is a sense of hopelessness about the future and decreased motivation or feelings of guilt. The perception is distorted for self and the world.
• Behavioral Symptoms: There are changes in appetite and weight. The sleep is disturbed and energy levels are decreased. The person feels emotionally withdrawn or isolated. There is reduced productivity or difficulty performing daily tasks.
• Physical Symptoms: The person has physical aches and pains. There are digestive issues such as changes in bowel habits. There is a feeling of tension or restlessness and changes in sexual desire or functioning. The person also experiences headaches and migraines.

 The severity and duration of symptoms of subsyndromal depression can vary in individuals. It is advisable to seek professional help if the symptom causes distress or impairment.

The following criteria are outlined by the DSM-TR to make the diagnosis of major depression: 

• Depressed mood
• Sleep disturbance
• Loss of interest or pleasure in activities
• Psychomotor changes
• Tired, fatigued, low energy, or complete routine tasks with decreased efficacy
• Having a sense of worthlessness or excessive, inappropriate, or delusional guilt
• Having suicidal ideation and thoughts about death
• Impaired ability to think, concentrate or make decisions

 A person should be suffering from five or more symptoms to be diagnosed with major depression. At least one symptom should be depressed mood or loss of interest or pleasure.

A person is diagnosed with subsyndromal depression if two to five symptoms are present for most of the time during two weeks period.

According to a 2013 review, subsyndromal depression is associated with an increased risk of psychosocial disability, major depression, social phobia, and generalized anxiety disorder, and also with decreased quality of life and increased societal and economic cost.⁽⁴⁾ More research is therefore vital for subthreshold categories of depression.

Subsyndromal depression has no definitive cause. Biological, genetic, environmental, and psychological factors can play a role.⁽³⁾

Some of the common causes of subsyndromal depression include: 

• Biological factors: A family history of depression or mood disorders can increase the risk of subsyndromal depression. Imbalance in the neurotransmitters such as serotonin, norepinephrine, and dopamine can play a role in regulating mood and thereby subsyndromal depression.

There can be fluctuation and imbalance in hormones in particular stages of life that can influence mood.

• Psychological factors: There are certain psychological traits such as high levels of neuroticism, low self-esteem, or a tendency towards negative thinking that may contribute to the development of subsyndromal depression. Negative thinking patterns, rumination, and distorted cognitive processes can influence mood and can contribute to the persistence of depressive symptoms. Also, childhood trauma, adverse childhood events, or dysfunctional family dynamics can increase the risk of subsyndromal depression in adulthood.
• Environmental factors: Certain environmental factors such as persistent stressors, significant life events, lack of social support, and also living in an environment with limited resources can contribute to the development of subsyndromal depression.

 The risk factors for subsyndromal depression may include:

• Suffering from chronic medical conditions including cardiovascular diseases, diabetes, or chronic pain.
• Substance abuse which includes using alcohol or drugs.

Having an understanding of the potential causes and risk factors can be helpful in targeting prevention and interventional strategies.

 There are several treatment and management approaches for subsyndromal depression. These include:

• Medications: The medications involved in the treatment of depression include antidepressants such as serotonin reuptake inhibitors.
• Psychotherapy: There are several therapies including interpersonal therapy and cognitive behavior therapy that can improve functioning and decrease depressive symptoms.⁽⁵⁾
• Lifestyle Modifications: Frequent exercise, eating a well-balanced diet, and getting optimal sleep can lessen the frequency of depression.⁽⁶⁾

 Subsyndromal depression is not the same as major depression, still paying attention to the symptoms and seeking treatment is essential, when needed.

 Prevention and early intervention can play a crucial role in addressing subsyndromal depression and minimizing its impact.

• Psychoeducation: Providing information and education on depressive symptoms, risk factors, and coping strategies can help individuals recognize early signs of subsyndromal depression and take appropriate actions.
• Mindfulness and Stress Reduction Strategies: These can help manage individual stressors, enhance self-awareness, and build resilience. These can help manage depressive symptoms.
• Social Support: Encouraging individuals to engage in positive social interaction, seeking emotional support from friends and family, and participating in community activities can help in reducing the feeling of isolation.
• Healthy Lifestyle: Promoting a healthy lifestyle can have a positive impact on mental health.
• Cognitive Behavior Strategies: This can modify negative thinking patterns and behaviors and associative depressive symptoms.
• Collaborative care: It involves a multidisciplinary approach involving the primary care provider, mental health professional, and other relevant healthcare professional.

 The prevention and early intervention strategies should be tailored to individual needs.

 Subsyndromal depression is less commonly understood. It is termed as subsyndromal as the person experiences fewer symptoms than major depression.

Subsyndromal depression puts a person at a higher risk of poor functioning, developing major depression, and other mental health conditions. Various treatment options such as psychotherapy, medications, and lifestyle changes are involved in the treatment of subsyndromal depression.