Mental illness covers a wide variety of disorders, from schizophrenia, depression, Alzheimer’s, anxiety and self-harm to eating disorders.

These disorders can be the outcome of many different kinds of experiences in a person’s life, from early childhood to later life events. Some examples:

  • chaotic, unsafe or dangerous environments (for example, living in a violent home, or living in a house with shedding asbestos, peeling lead paint, or toxic drinking water)
  • early life serious losses or traumas (such as the death of a parent in childhood, or being abused or neglected)
  • loss of social support (due to death of a loved one, divorce, moving away from friends and family, break up of a relationship, loss of a job, or loss of trust)
  • unhealthy social conditions (such as poverty, homelessness, and community violence)
  • experiences that undermine self-confidence (such as social or work-related failures)
  • learned helplessness and negative thought patterns (chronic or repeated stressful events leading to the belief of helplessness, reinforced by lack of control over the situation)
  • chronic illness (such as heart disease, stroke, HIV, Parkinson’s, cancer, or diabetes) that seriously restrict activity
  • side effects of medications (for example, blood pressure medications and numerous other drugs)
  • hormonal changes (stage of life adjustments, such as the onset or end of menstruation that affect mood)
  • substance abuse: alcohol and some drugs are known to have depressive effects, and the negative social and personal consequences of substance abuse can also be a contributing factor to depression (however, it is not clear which comes first – depression and attempts to control it with substances, or the use of substances that then cause depression)
  • genetic causes: people with close family members who suffer from depression are more prone to depression (however, since no gene for depression has been found, this may be environmental rather than genetic)
  • biochemical causes (an imbalance of neurotransmitters such as serotonin is known to affect the processing of thoughts and emotions)