A couple of years ago I was at a local psoriasis supporters meeting and was chatting to a guy who was very depressed about his bad psoriasis. It was an interesting chat and i was glad to be supported in my opinions by a lady who had similar experiences to what I have had.
This guy is an inside person. He is single and with no significant other in his life. He has psoriasis that is treated by a dermatologist. He told me that nothing that the dermatologist had tried worked for his psoriasis and he was going to have biologic injections to sort it out. I am not a lover of the concept of those injections, they are a crazy price that just pushes up the cost of health-care unnecessarily and they have potentially lethal side-effects. So I asked him a few questions about his lifestyle and what treatments had been tried. It was enlightening.
Living alone and not caring for cooking, he eats out all the time. Mostly fast food burgers, fries and sodas. I asked why he doesn't opt for the much healthier salads now offered by most fast food chains but he doesn't like salads. A diet composed almost entirely of beef burgers, fries and sodas is guaranteed to mess up your body in one way or another. For him it shows as psoriasis, for others it might cause type 2 diabetes, heart problems, morbid obesity, cancer or other nasty conditions.
He doesn't do any outdoor activities, at all. He has an indoor job and stays indoors all weekend as well. So, he gets virtually no sunshine on his body. He does not use UV light in the treatment of his psoriasis and he does not take vitamin D supplements. He was surprised to hear that UV light is a treatment for psoriasis as it had not been offered by his dermatologist. He suffers from chronic depression and is on anti-depressant drugs. He said that it was his psoriasis that caused him to be depressed.
I urged him to sort out his diet by eating more vegetables, fresh salads etc and to get out into the sun. Those changes should improve both his psoriasis and depression problems.
The human body needs vitamin D to be healthy. Most of this is processed by our bodies from exposure to sunlight. The amount of sunlight that our bodies can take is controlled by the pigments in our skin, so people who naturally lived close to the equator are dark-skinned to minimise absorption and those from higher latitudes closer to the poles have lighter skins to maximise absorption. If dark-skinned people move into areas of low sunlight they suffer from depression because they are deficient in vitamin D. They must either get more sunlight to make more vitamin D or they must take vitamin D supplements to compensate.
The answer to this depression by many doctors is to just medicate with anti-depressants. If they prescribed vitamin D instead, there would be much less need for anti-depressant drugs.
Depression is a problem in modern society for various reasons, including pressure of work, spending too much time working at indoor jobs and watching sports on TV instead of outdoors. Added to this is the concern for the dangers of exposure to UV rays, so everyone covers themselves with sunblock creams and sprays to block out the UV when they do get into the sun. Blocking out the UV rays stops your body from producing vitamin D, so you end up with a deficiency and a chance of depression. The answer is to expose yourself, unprotected, to natural sunlight for a few hours each week, preferably 30 minutes or so each day. The more skin that you can expose, the shorter the time can be. Twice as much exposed skin needs half as much sunlight time to process the same amount of vitamin D.
If you have a private garden or balcony, strip completely naked and absorb the sun all over. It will help the psoriasis in your groin much more to be exposed to some direct sunlight than to get it indirectly through vitamin D processed through exposure of your arms and legs. It is also surprisingly invigorating to feel the warmth of the sun and the feel of a breeze on parts of your body that are normally covered.
Don't overdo it though. Sudden exposure of a pale body to many hours of sunshine will result in sunburn. Damage from repeated sunburns will build up in your body and you can expect skin cancer to be in your future. Peeling skin after sun tanning is an indication that you are over-doing it. Blisters are a major no-no and an indication that you are looking for trouble. I have been in the sun many thousands of hours in my 63 years but have not peeled in at least the last 30 years and have not blistered since I was a teenager.
Building up a tan slowly will give some protection from damage and reduce the chances of skin cancer. Maintaining a constant moderate tan will be safer than tanning excessively every summer vacation and staying out of the sun the rest of the year.