Satisfied sex life is the most essential part of almost every individual in the world, be it male or female. Every human being on earth is gifted with varying degree of sexual orientation, some people are just average, some are very strong in it who can satisfy their partners almost 100% each time they have intercourse. Some people experience problem in their sexual life because they unable to keep the erection for longer time and penis (male sexual organ) fall flaccid even before their partner is satisfied completely. Today, 1 out of 10 men in the world is suffering from erectile dysfunction. Erectile dysfunction (ED) is a sexual disorder where a man unable to attain and maintain a penile erection sufficient to favor satisfactory sexual intercourse. ED is one of the common chronic medical disorders in men over the age of 40 years. No doubt, this problem is a major quality of life issue for an increasingly healthy ageing population.
In men, erection is associated with strong blood flow in penis. Men get aroused through sensory or mental stimulation towards the sexual encouragement, which results in signals from the brain to the fibrous tissues in the penis causing these tissues to relax and allow a strong flow of blood inwards. Then erection is conserved by allowing the tissues in the outer line of the penis to contract and trap the blood which has flown in. This entire process of attaining erection and preserving it occurs as a result of chain of various processes, which are strictly sequenced. Erectile dysfunction (ED) occurs when any of the events in the chain distorted or results in loss of control and the penis cannot hold blood in the fibrous tissues. This situation leads to loosening of the penile erection well before the climax leads to erectile dysfunction. 
Physiological causes lies behind erectile dysfunction are side effects of medicines such as antihistamines, antidepressants, tranquilizers, appetite suppressants, and cimetidine, injury to genitals that lead to disturbance in the natural process of attaining erection, sudden fall in the desire for sex and ability to hold erection due to diseases such as chronic diseases like diabetes, diseases related to nerve systems, vascular and heart problems, various sclerosis conditions, kidney diseases and weight increase and certain bad habits such as overdoing masturbation, alcohol or tobacco consumption, and drugs consumption such as heroin, cocaine, morphine. This leads to lack of desire in sex and damaged genital tissues and causes the penis to lay flaccid rather than attaining a strong erection. The psychological cause will be due to a person's mental inability to concentrate and attain full confidence in sexual relationship and mental imbalance. This often led to lack of desire for sex and they cannot hold their erection rather they fail to even erect their penis. Arousal level is physiological and psychological state involving the activation of the reticular activating system in the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of alertness and readiness to respond.
In the earlier part of this essay, the cause of ED which is depression will be discussed (depression causes ED). The main risk factor of ED will be demonstrated in the following part of this essay (ED causes depression).
Psychological factors are responsible for about 10%-20% of all cases of ED. Depression is a major psychological cause of ED. Depression is a common mental disorder that presents with low in mood, loss of interest or pleasure, feelings of guilt or low self-worth, disturbed sleep or appetite, low energy, and poor concentration. Depression can be work related, financial, sexual, marital or could be due to other reasons. In some cases, the psychological effects of ED may arise from childhood abuse or sexual trauma. These problems can become chronic or recurrent and lead to substantial impairments in an individual's ability to take care of his or her everyday responsibilities.
Depression can cause psychological ED because it interferes with the brain function necessary to stimulate sexual arousal and produce an erection. It also suppresses positive feelings and emotions, which inhibit libido and the desire for sexual activity. So depression can cause ED even when a man is completely comfortable in sexual situations. Elderly man basically will be facing loss income and work. It is difficult for many men to accept retirement because it's a sudden change in their routine. In addition the death of family and friends can trigger depression in men which will further lead ED. Further more, older men may suffer from medical conditions such as heart diseases, diabetes, renal failure or cancer will have depression and this can contribute ED. Medical conditions is said to be the factor for ED because the patient will be down mentally and physical pain will dampen the desire and contribute to short-lived erections.
When depression is the cause of ED, depression will be the condition to be treated in order to prevent ED. Depression can affect us biologically as much as psychologically and that these aspects constantly interact. Positive and negative signals can have a significant impact on various systems in the brain and in particular stress systems and systems that control mood, such as 5-HT (serotonin). These systems are affected by negative and positive signals in different ways. In very general terms negative signals such as losses and threats tend to increase depression and can adversely affect 5-HT, whereas positive signals (approval, love) tend to reduce depression and increase 5-HT.
Depression can be treated with anti-depressant medications but is it found that anti-depressants can promote ED. ED in a patient being treated with anti-depressant medications may be due to the underlying depression. The incidence of such sexual side effects such as ED can be as high as 92% for some antidepressants. Anti-depressants cause ED because it suppresses the serotonin production in the brain. So when serotonin production is reduced, this may reduce the desire for sexual activity. So in this case antidepressant's which is used to treat depression can be directly linked with ED. 
Psychological treatment of depression (psychotherapy) can assist the depressed individual in several ways. First, supportive counseling helps calm the pain of depression, and addresses the feelings of hopelessness that accompany depression. Second, cognitive therapy changes the unrealistic expectation and overly critical self-evaluations that create depression and sustain it. Cognitive therapy helps the depressed person recognize which life problems are critical, and which are minor. It also helps the patient to develop positive life goals, and a more positive self-assessment. Third, problem solving therapy changes the areas of the person's life that are creating significant stress, and contributing to the depression. This may require behavioral therapy to develop better coping skills to assist in solving relationship problems. Most men have experienced ED during periods of depression, however these episodes are temporal. Full sexual function returns once the depression has been treated.
Some men may be worried if the general practitioners or other health care providers are the proper place to discuss ED. They many feel uncomfortable to discuss their sexual lives because they are not sure if the physician will consider ED as a serious problem. They may worry that they will embarrass the physician by discussing about it because of their own discomfort with talking about sexual issues or believing that ED is not part of the health care. Physicians or other health care providers do not raise the topic unless the patient does. As a result of this, ED often goes undiagnosed and untreated for a long time. This untreated condition will later on root to depression (ED causes depression). 
Lack of sexual knowledge in individual experiencing ED will lead to depression. Men with ED and their partners often lack a full understanding of sexual process or have unrealistic expectations regarding sexual performance and satisfaction. Men account ED as a real challenge to their pride. Moreover, many men believe a number of myths surrounding potency problems by past actions such as infidelity or masturbation. They may perceive ED as an inadequacy and suffer from silence rather than risk exposing of this perceived inadequacy. This might drive to psychological underpinnings.
In men of all ages, ED may decline the desire to initiate sexual relationship because of fears unsatisfactory sexual performance or rejection. There will be negative effect on overall health of older males because they are usually sensitive to the social support of intimate relationships and there will be withdrawal from such relationships due to fears. They may have guilty feeling because of their inability to fulfill their role as a man. It is also common for man to worry that ED is the sign and symptoms of physical decline toward old age and death.
When a man is suffering from ED, the couple will be facing emotional breakdowns. Many women may validate an erection as the demonstration of true love and desires her. Hence the absence or poor erection makes the partner to believe that their man is not attracted to them. This problem can branch into a major communication breakdown in couple. Over time, men will avoid to hug, kiss, hold or even touch their partner because of the fear that this action may lead them on to sexual intercourse. Men may create arguments to avoid sexual encounters. As the outcome, both the couple feels isolated, worthless and distressed. This can end up marital breakdown and divorce.
So when ED is the main cause of depression, ED has to be treated in order to reduce or inhibit depression. One of the most popular medical therapies nowadays is Sildenafil, or popularly known as Viagra. This drug improves blood flow to the penis, resulting increased smooth muscle relaxation and better erection and thus ED can be treated. The first line therapy is the mechanical vacuum devices which cause erection by generating partial vacuum, which draws blood in to penis engorging and expanding it. It is safe, least expensive, effective, reusable and available over the counter.
When the treatment options have been discussed with the patient, the partner should be involved whenever it is possible. The partner's participation is beneficial and helps to enhance couple's intimacy and ability to communicate about sex. The patient and the partner will need to understand and learn to accept that when the drug therapy and mechanical devices fails to produce erection, surgery or penile implant is the last resort. Of all the approaches penile implant carries the most permanent consequences. Once the implant is implanted, the normal spongy tissue will be damaged and destroyed, and the chances to erect naturally are very minor. So the good outcome from the physician's perspective may not satisfy either the patient or the partner. It is important for both the patient and the partner to accept the treatment for the successful outcome.