Could There Be a Medical Cause for My Depression?
Depression is a real health condition in its own right. But sometimes physical illness, sleep problems, hormonal changes, nutritional deficiencies or medications can contribute to symptoms that look or feel like depression.
- Depression does not always have one single cause.
- Physical illness, chronic pain, poor sleep and hormonal changes can affect mood.
- Some nutritional deficiencies and medication effects can produce symptoms that overlap with depression.
- Finding a physical contributor does not mean depression is not real.
- Persistent, changing or unusual symptoms are worth discussing with a health professional.
Depression is not always one simple thing
When someone develops depression, it is natural to look for a single explanation.
Was it stress?
A difficult life event?
Hormones?
Illness?
Sleep?
Sometimes there is a clear trigger.
But often several things are happening at the same time.
Sleep, pain, hormones, illness, medication, nervous-system function, life circumstances and mood can all influence one another.
What can depression feel like?
Depression is not only feeling sad.
It may include:
- low or flat mood
- loss of interest or enjoyment
- very low motivation
- fatigue or feeling slowed down
- difficulty concentrating
- memory problems
- sleep changes
- appetite changes
- irritability
- withdrawal from other people
- feeling hopeless or overwhelmed
The difficulty is that several of these symptoms can also occur with physical health problems.
Medical and physical factors that can contribute
Thyroid problems
An underactive thyroid can cause low energy, slower thinking, difficulty concentrating and low mood. Other clues can include feeling unusually cold, constipation, dry skin or weight changes.
Iron deficiency or anaemia
Low iron or anaemia can contribute to fatigue, weakness, headaches, dizziness, breathlessness and reduced concentration. Feeling physically depleted can also have a substantial effect on mood.
Vitamin B12 or folate deficiency
Deficiency can cause fatigue and cognitive changes. Vitamin B12 deficiency can also affect the nervous system and may be associated with psychological symptoms.
Sleep disorders
Poor-quality or repeatedly interrupted sleep can affect mood, concentration, energy and emotional regulation. Sleep apnoea is one possible example.
Hormonal changes
Pregnancy, the postpartum period, menstrual-cycle changes, perimenopause and menopause can affect mood in some people.
Chronic pain
Persistent pain can reduce sleep, activity, social connection, independence and enjoyment. Depression and chronic pain can also influence one another.
Chronic illness
Long-term illness may affect mood through physical symptoms, biological effects, reduced capacity, uncertainty, treatment burden and changes to everyday life.
Medication effects
Some medicines can affect mood, sleep, alertness or energy. Timing can matter if symptoms appear after starting, stopping or changing a medication.
Sometimes the biggest clue is what changed
A sudden change in mood alongside a new physical symptom, illness, medication, hormonal transition or major change in sleep can be useful information.
It does not tell you the cause by itself, but it can help a health professional know what else may be worth considering.
1. Thyroid problems
An underactive thyroid can sometimes cause symptoms that overlap with depression.
These can include:
- low energy
- slowed thinking
- difficulty concentrating
- low mood
- feeling unusually cold
- constipation
- dry skin
- weight changes
Thyroid function can usually be investigated with blood testing when clinically appropriate.
2. Iron deficiency and anaemia
Sometimes what looks like very low motivation is partly severe physical depletion.
Iron deficiency or anaemia can be associated with:
- fatigue
- weakness
- dizziness
- headaches
- shortness of breath
- palpitations
- difficulty concentrating
This does not mean iron deficiency causes every case of low mood.
But significant fatigue alongside depression may justify looking at the broader physical picture.
3. Vitamin B12 and folate deficiency
Vitamin B12 and folate deficiencies can cause fatigue and problems with thinking. Vitamin B12 deficiency can also affect the nervous system.
Possible features can include:
- extreme tiredness
- low energy
- weakness
- pins and needles
- numbness
- memory or concentration problems
- balance problems
- psychological symptoms
Testing is most useful when symptoms, diet, medication history or other risk factors suggest a deficiency may be possible.
4. Sleep problems
Sleep and mood are closely connected.
A person may technically spend enough hours in bed but still have poor-quality or repeatedly disrupted sleep.
Sleep apnoea, for example, can be associated with:
- loud snoring
- breathing pauses
- gasping or choking during sleep
- repeated waking
- severe daytime tiredness
- difficulty concentrating
- morning headaches
- mood changes
Someone can feel unable to initiate activities because they are physically exhausted. Depression can also cause fatigue, and both problems can exist together.
5. Hormonal changes
Hormonal transitions can affect mood in some people.
This can include changes associated with:
- the menstrual cycle
- pregnancy
- the postpartum period
- perimenopause
- menopause
- some endocrine conditions
If mood symptoms appeared around a significant hormonal transition, it can be helpful to mention the timing rather than viewing the mood change in isolation.
6. Chronic pain and chronic illness
Chronic illness can affect mood in many different ways.
There may be:
- persistent physical symptoms
- pain
- fatigue
- poor sleep
- reduced independence
- loss of work or usual roles
- less social contact
- uncertainty about the future
- ongoing treatment demands
People with chronic illness are at increased risk of depression, but that does not mean their physical symptoms are caused by depression.
Both parts of the picture may need support.
7. Post-viral illness and reduced physical capacity
Some people experience persistent fatigue, cognitive difficulty, sleep disturbance or autonomic symptoms following an infection.
From the outside, reduced activity can sometimes look like loss of motivation.
But there is an important difference between:
and “I want to do this, but my body cannot reliably sustain it.”
Someone can also experience reduced physical capacity and depression at the same time.
8. Medication effects
Some medications can affect:
- mood
- energy
- alertness
- sleep
- concentration
If symptoms started or became noticeably worse after:
- starting a medication
- changing the dose
- reducing a medication
- stopping a medication
mention that timing to the prescribing clinician.
Do not suddenly stop prescribed medication without appropriate medical advice.
9. Neurological and other medical conditions
Some neurological and systemic medical conditions can affect mood, cognition or behaviour.
This does not mean that someone with depression should assume they have an undiagnosed neurological disease.
But new mood changes alongside significant new neurological symptoms deserve medical assessment.
These might include:
- new weakness
- new numbness or altered sensation
- major balance problems
- significant cognitive change
- seizures
- new movement symptoms
- marked or unusual behavioural change
What else may be worth looking at?
Choose anything that has been part of your picture. This cannot diagnose the cause of depression. It may simply help you notice what could be useful to mention at a health appointment.
It may be worth looking at the whole picture
A useful question may be: what changed?
If depression or severe fatigue appeared at a particular point, think about what else was changing at the time.
For example:
- Did an illness begin?
- Did sleep become much worse?
- Did pain increase?
- Did periods or hormones change?
- Did you start or stop a medication?
- Did your physical capacity suddenly reduce?
- Did a major stressful or traumatic event occur?
- Did several of these things happen together?
But it can help build a clearer picture of what was happening when symptoms developed.
When might a medical review be particularly useful?
Consider discussing the broader physical picture with a health professional if low mood or loss of functioning:
- appeared suddenly or feels unexplained
- is accompanied by marked fatigue or weakness
- started after a medication change
- appeared around a major hormonal transition
- occurs alongside unexplained weight or temperature changes
- comes with dizziness or palpitations
- includes numbness, weakness or other neurological symptoms
- occurs with loud snoring or severe daytime sleepiness
- followed an infection or prolonged illness
- is significantly affecting everyday functioning
It does not have to be either depression or physical illness
This distinction is important.
Someone can have depression and a physical illness.
They can have chronic pain and depression.
They can have sleep apnoea and depression.
They can have a hormonal transition, major life stress and depression at the same time.
The aim is not to prove that symptoms are either “medical” or “psychological.”
It is to understand what may be contributing so that the right things can be supported.
Physical illness + reduced capacity + poor sleep + stress + depression can all exist in the same person.
Look at the whole person, not just the label
Depression deserves proper care.
So do persistent physical symptoms.
Looking at sleep, physical health, medications, hormones, pain, nutrition, life circumstances and mood together does not minimise depression.
It may help build a more complete picture of what is making life difficult and what support could genuinely help.
If depression feels unsafe
Depression can sometimes involve thoughts of suicide, self-harm or feeling unable to stay safe.
If this is happening, seek urgent support from a health professional, local crisis service or emergency service.
You do not need to know why you feel this way before asking for help.
Not sure what is making things hard?
Explore ALPIMS by what you are experiencing rather than needing to know the diagnosis first.
