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Les causes de la dépression : entre biologie et environnement
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The causes of depression: between biology and environment

IRIS Prévention
8 July 2026
Depression never has a single cause. It is born from the meeting between vulnerability and life circumstances.

Les causes de la dépression : entre biologie et environnement

“Why me? » is a common question when faced with depression. The answer is rarely simple, because this disease results from several factors which add up: a biological part, a psychological part and a part linked to the environment. Understanding this model helps you relieve your guilt and take better care of yourself.

1. The multifactorial model

Specialists speak of a “bio-psycho-social” model. None of these factors is enough on its own: it is their combination that turns things around. In areas of vulnerability, a triggering event can be enough to cause the disease to appear.

2. Biological factors

Depression is accompanied by changes in brain function, particularly in the neurotransmitter systems involved in mood. There is also a genetic part: having a family history increases the risk, without making it inevitable.

FactorRole
NeurobiologyImbalances in mood circuits
GeneticsIncreased family vulnerability
HormonesPossible role (postpartum, thyroid)

3. Psychological and social factors

Certain traits (high demands on oneself, tendency to rumination), difficult early experiences or low social support increase vulnerability. Life events (bereavement, separation, job loss, isolation, chronic stress) often play a triggering role.

4. Why understanding the causes helps

Understanding that depression has multiple origins allows us to escape from guilt: we are not depressed “out of weakness”. This also opens the way to global care, acting on the body, thoughts and environment at the same time.

Each story is unique: identifying your own factors, with the help of a professional, is part of the path to recovery.

💡 tips to remember

    • Depression never has a single cause: it results from a combination of biological, psychological and environmental factors.
    • There is a genetic part: family history increases the risk without making it inevitable.
    • Life events (mourning, separation, isolation, chronic stress) often play a role a role of trigger on a vulnerable terrain.
    • Understanding the multifactorial origin helps to relieve guilt: we are not depressed “out of weakness”.
    • Comprehensive care acts on the body, thoughts and environment at the same time: identifying your factors is part of the path.