Social isolation is a known risk factor for veteran suicides. Spending a lot of time alone is not, by itself, the reason for the increase in suicide risk. It has to do with how isolation affects mental health. Humans are social by nature. When people have virtually no contact with others and lack support they become lonely, anxious and depressed. In addition their problem solving and basic thinking skills decline. Simply having someone to talk to improves mental health and the opposite makes mental health worse.
Physical Versus Emotional Isolation
We generally think of isolation as being physically separate from others. However, it is possible and, in fact, common to be physically with others but emotionally disconnected. A person may have no choice in becoming isolated from others. Or they may choose to isolate. In either case an extended period of social isolation can be harmful both mentally and physically. When individuals choose to isolate from others it can be because of fear or because of what are essentially hurt feelings. Many times this sort of isolation is more permanent and damaging to mental health.
Physical Results of Social Isolation
People who are socially isolated for long periods of time commonly have a higher risk of heart disease. They tend to have higher blood pressure than others. Their immunity is weaker than those who are not isolated. And people who are socially isolated tend not to live as long as those who are socially engaged. Simply being alone much of the time is not especially dangerous. The connection between isolation and physical problems commonly is mediated by one’s emotions.

How Mental Health Is Affected by Social Isolation
Many research studies have confirmed that strong social connections go hand in hand with a lower risk of depression compared to those who are socially isolated. Work stress is typically higher in socially isolated individuals who, in turn, tend toward substance abuse with alcohol and drugs. Life satisfaction is routinely lower in socially isolated individuals. Those who are isolated by choice or by circumstances are generally less able to handle the routine stresses of life.
Being Isolated Means Being Without Help
Routinely being with others result in a feeling that one belongs to a group or something important. Other people provide meaningful support on our lives. When that support is missing a person has to confront life’s troubles alone, without advice, and without physical help. As much as self-reliance is important in life, everyone needs advice and or help at times.
Are You Socially Isolated?
It is common for a person to become accustomed to the routines in their life. It is easy to fall into a rut and not realize that parst of your life are not especially healthy. Some indications that a person is getting socially isolated are dropping out of events or activities that they used to engage in. Routinely spending most of the day alone with absolutely no contact with others is not normal or healthy. When you realize that you have no one to turn to for help in times of trouble or simply to chat, you are socially isolated. If you virtually never talk on the phone to anyone or communicate by text messages or video calls you are getting socially isolated. This sort of situation leads to a lack of close and intimate connections and lack of meaningful contacts.

How Do You Feel?
It is useful for a person to routinely take their emotional temperature. Are you feeling rejected, sad, or lethargic? Are you excessively sensitive to stimuli in your immediate environment? Do you feel lonely even when you are with people? Social isolation and loneliness are not necessarily the same thing. Also choosing solitude in order to think and sort things out is not the same as social withdrawal and social isolation. The one can be emotionally healthy and the other can be emotionally damaging.
Social Isolation As a Risk Factor for Suicide
Social isolation can be caused by depression, financial difficulties, relationship breakups, and mental illness issues like PTSD. All of these are by themselves risk factors for suicide. By adding social isolation to the picture a person at risk for suicide is without help and emotional support. Reestablishing social connections with others is an effective way to start dealing with the other issues that increase suicide risk.