Depression.

Mood disorder that causes a persistent feeling if sadness and loss of interest in things and people.

It is also referred to as major depressive disorder or c******l depression. This disorder usually affects  how one feels, think and behave which eventually leads to different emotional and physical problems.

Depression usually requires a medical diagnosis. But there are indices  that would act as pointers die one to seek medical help

Mood

such a person exhibits anxiety, general discontent,  loss of interest in things and activities that usually brought fascination. Mood swings,  sadness etc.

Behavioural Attitude. 

Excessive show of emotions like crying,  agitation,  even laughing unnecessarily. High show of irritability,  isolation from social activities.

Sleep

Excessive sleeping,  restlessness ,insomnia, rising early even after sleeping late.

Wholeness of the body.

Excessive hunger, tiredness, loss of appetite.

Weight

Excessive weight gain or excessive w*********s. This is attributed to loss of appetite or excessive eating.

Lack of concentration,  slowness in activity,  or suicidal thoughts and actions.

Once all of these are noticed consult a doctor  for medical advice.