What should you know about biological causes of depression?

Depression does not have one biological cause that applies to everyone. Family vulnerability may influence how the brain responds to stress, while changes in sleep, appetite, energy and concentration can accompany depression. Thyroid problems, anaemia, chronic pain, neurological illness and some medicines can produce symptoms that overlap with depression, so a clinician may check your physical health and treatment history.

Insomnia and depression can occur together, and poor sleep may worsen mood, attention and irritability. Feeling anxious, fatigue and daytime sleepiness may also appear in depression, but these symptoms do not identify one cause on their own. A careful conversation helps separate overlapping problems.

Arrange a medical assessment if low mood, loss of interest, tiredness or concentration problems are affecting daily life. Write down when symptoms began, how sleep and appetite have changed, medicines and supplements you use, alcohol or drug use, and any relevant family history. Your clinician may discuss an examination, selected blood tests, talking therapy, medication or a combination. Keep taking prescribed medicine until you have discussed a change, and build a regular routine around sleep, food, movement and contact with supportive people.

Seek urgent help now if you may harm yourself, cannot stay safe, hear commands to hurt yourself or someone else, or feel detached from reality. Contact emergency services or go to the nearest emergency department, and involve a trusted person if possible. Arrange prompt medical review for rapidly worsening mood, severe agitation, several nights of very little sleep with unusually high energy, or new confusion. These changes can signal a condition needing immediate assessment.

Could a physical condition or medicine be contributing? Which symptoms point toward depression, anxiety or a sleep disorder? Do I need blood tests? What treatment choices fit my situation? How will we monitor mood, sleep and safety, and who should I contact if things worsen?