Types of mental ill health and mental disorders

Some mental ill-health symptoms can develop and be diagnosed as mental disorders. By understanding some of the consequences of mental ill-health, organisations and OSH professionals can better understand how to support and help workers to reach a more positive mental state. Supplementary to this, the information can help when implementing prevention strategies. If this is ignored, organisations potentially risk contributing to some workers developing mental ill-health and mental disorders.


It is natural for people to feel emotionally strained, worried, nervous or fearful at times. These emotions stimulate the body’s survival mechanisms to prepare us for action against anticipated danger and misfortune. These mental stimuli are collectively known as ‘anxiety’ and can modify brain processes and behaviour.

Anxiety can become a mental disorder when it becomes uncontrollable, unexpected and unhelpful. It can seriously affect someone’s life, work and health.

anxiety disorders diagram  
Anxiety disorders  



Depression can be described as a ‘lowering of feelings’ that affects emotional states, thoughts, self-esteem, happiness and self-worth. It can last for short or prolonged periods. When depression becomes more developed, it can be described as feeling like a physical disease that has overwhelmed the body and the brain. This gives the conception that the psychological condition can feel like it has become a physical condition.

It is normal to feel ‘down’ or ‘low’ at times in response to traumatic, difficult or emotionally demanding ordeals. However, if someone is unable to make a transition from this temporary negative state to a more positive coping state, they may have depression.

depression disorders diagram  
Depressive disorders  


Post-traumatic stress disorder

Those who are exposed to traumatic events such as workplace incidents, accidents, bullying, harassment, violence or abuse, or other stress-inducing events may develop post-traumatic stress disorder (PTSD). Those with PTSD are unable to eliminate thoughts and emotions associated with injury, loss, danger, anger or grief that then influence their behaviour.

Many associate PTSD with military combat experiences, but PTSD extends much further than this and can be caused by varying traumatic experiences – for example, events    that include a threat to life such as the death of a relative or witnessing a severe injury in a workplace.

Symptoms can develop within three months (approximately) of a traumatic (trigger) event, or they can develop many years later. The symptoms interfere with the individual’s work, everyday life and social relationships.

Most people can recover from PTSD naturally, or by communicating with others, or with professional therapy.

Vicarious trauma / secondary traumatic stress

This type of mental ill-health can occur in individuals due to indirect exposure to emotional trauma that somebody else has experienced. It can also occur when someone is exposed to graphic media or information such as disturbing news accounts and traumatic stories (audio or visual).

Those who work in high-stress or traumatically exposed sectors of work such as child abuse investigators, judges and public services could be more likely to experience the disorder.

Trigger experiences could be related to abuse, violence, workplace incidents and natural disasters.

Organisations and OSH professionals should consider the potential for vicarious trauma/ secondary traumatic stress (VT/STS) if a worker or group of workers is exposed to a traumatic workplace event (such as a fatal incident or serious injury). The event may affect more workers indirectly than those directly exposed to the event.

VT/STS can occur due to a one-time exposure event or after repeated exposures.