When Tiredness Isn’t Just Physical: Understanding Psychologically Driven Fatigue

Tiredness is one of the most common complaints presented in both primary healthcare and mental health settings. Yet while it is often attributed to physical causes—such as sleep deprivation, anaemia, or hormonal imbalances—fatigue can also be rooted in psychological origins. Understanding this dimension is essential, particularly when physical investigations return normal and tiredness persists.

Psychological Fatigue: A Clinical Perspective

In psychological terms, tiredness is not simply a lack of energy, but rather a subjective sense of exhaustion that is disproportionate to activity level and often unrelieved by rest. This form of fatigue is associated with multiple mental health conditions and is classified under various categories in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition).

Relevant DSM-5 Categories Include:

Major Depressive Disorder (MDD) – Fatigue or loss of energy is one of the core diagnostic criteria.

Generalised Anxiety Disorder (GAD) – Chronic tension and worry can lead to emotional exhaustion.

Somatic Symptom Disorder – Persistent somatic symptoms, including fatigue, that cause significant distress.

Persistent Depressive Disorder (Dysthymia) – Low-grade but chronic fatigue is common.

Chronic Stress-Related Disorders – Including adjustment disorder and burnout.

Recognising the Signs of Psychological Tiredness

It can be difficult to distinguish psychological tiredness from physical causes, especially as they often coexist. However, some characteristics are suggestive of a psychological origin:

Psychological Fatigue Physical Fatigue
Not improved by sleep Often improves with rest
Fluctuates with mood or stress Stable across the day
Accompanied by low motivation, anxiety, or sadness May occur without emotional symptoms
Difficult to describe or localise Often associated with muscle weakness or
Can feel ‘mental’ (brain fog, indecision) specific symptoms
Often ‘bodily’ (heavy limbs, sluggishness)

A study published in the British Journal of General Practice (2016) found that up to 75% of patients presenting with fatigue had no identifiable physical cause, and many were later found to have psychological factors contributing, particularly low mood, stress, or unrecognised anxiety.

Why Diagnosis Can Be Challenging
Diagnosing psychologically driven tiredness is complex. It often requires:

• Exclusion of physical illness (e.g. thyroid issues, sleep apnoea, chronic infection)

• Detailed psychological history, including patterns of mood, stress, trauma, and life events

• Careful screening tools such as:

• PHQ-9 for depression

• GAD-7 for anxiety

• Chalder Fatigue Scale

There is also a stigma associated with psychological fatigue—many individuals feel invalidated when told their symptoms are “in the mind.” However, this reflects a misunderstanding of the mind-body connection: psychological fatigue is just as real and impactful as any physical illness.

The Therapeutic Approach
At The London Psychologist Clinic, we approach fatigue holistically, integrating psychological, behavioural, and lifestyle interventions.

Treatments may include:

Cognitive Behavioural Therapy (CBT) – Especially effective for fatigue linked to anxiety, low mood, and unhelpful thought patterns.

Mindfulness-Based Stress Reduction (MBSR) – Helps manage emotional overload and improve energy regulation.

Behavioural Activation – Targets low motivation by gently reintroducing enjoyable, purposeful activity.

Sleep restructuring – To correct unhelpful sleep habits or insomnia.

Nutritional and lifestyle consultation – When relevant, to rule out behavioural contributors (e.g. caffeine overuse, irregular routines).

Collaboration with GPs or psychiatrists – For medical management if needed (e.g. antidepressants or sleep aids).

Case Study (Anecdotal)
A 38-year-old teacher presented with chronic fatigue lasting 18 months. Extensive medical testing showed no abnormalities. After a psychological assessment, she was diagnosed with Persistent Depressive Disorder. With regular CBT and gradual routine restructuring, she reported an 80% improvement in energy and functioning over three months.

Psychological tiredness is common but often under-recognised. It is essential for clinicians—and individuals themselves—to consider mental health as a cause of persistent fatigue, especially when tests are normal and rest doesn’t help. The mind and body are not separate systems: emotional strain, unresolved stress, and mental health conditions can profoundly affect energy.

At The London Psychologist Clinic, we offer compassionate, evidence-based assessment and therapy for those experiencing fatigue that feels unexplained or overwhelming. If you or someone you know is struggling with unexplained tiredness, we encourage you to reach out.