What is HPPD?

HPPD is a condition which affects psychedelic drug users. It is characterized by lingering hallucinations and visual disturbances after the drug effects have worn off. HPPD can vary in its severity from extremely intrusive to minor. Accompanying these visual changes there can sometimes also be negative emotions and anxiety. This too can vary in its severity.

HPPD can manifest as a wide range of visual symptoms. Some of these might be:

Perception of movement in peripheral visual field
Blurring of small patterns
Halo effects
Phosphene CEVs
Increased colour saturation and vibrancy
Shimmering effects
Lingering afterimages
Geometric patterns OEVs
Size distortions

What causes HPPD?

The difference between HPPD and Flashbacks

Flashbacks and HPPD are often inaccurately conflated. Flashbacks are a phenomenon involving sporadic temporary re-livings of a trip when not on a drug, perhaps weeks or even months after the trip took place. This can include not just visual disturbances but the emotions and feelings of a trip too.

HPPD is continually present visual disturbances and hallucinations after use of a psychedelic drug. This need not involve a re-living of the emotions from a trip, though its often associated with anxiety, but not always.

The link between HPPD and Anxiety.

HPPD is often caused by a bad trip. While most people who have bad trips do not develop HPPD, nonetheless most people who develop HPPD had a bad trip.

There are many triggers people experience which makes their HPPD worse. These are often related to negative emotions, which could suggest another link between HPPD and bad trips.

Triggers can include:

Anxiety
Stress
Drug use
Tiredness
Obsessive focus on HPPD symptoms

How common is HPPD?

There is very little research into this question. Estimates vary wildly between 0.12% and 4% of users. It seems to be quite rare.

What is the prognosis of having HPPD?

Some people recover completely from HPPD, but it's not known what the proportions who do or don't are.

There are often two separate elements involved in a case of HPPD - the visual disturbances themselves, and the negative emotions and mental states associated with them. Some people find that the visual disturbances themselves go away after a period of time. However, even if they do not, it's still possible to deal with the negative mental state even if the visual disturbances persist.

What are the medical treatments for HPPD?

HPPD is not well understood. There is no known cure. However as the list of triggers demonstrate, there are changes to lifestyle which could help alleviate the symptoms. Avoiding drug use and stress, trying not to think about the HPPD symptoms, exercising and eating healthily, socialising, ultimately doing positive things.
It's easier said than done to simply ignore the HPPD symptoms, as they can be disturbing and cause many fears such as that it will never go away. The psychological trick to make here is to learn to accept the symptoms as normal. You've been the unlucky receiver of a negative medical condition. You can help yourself if you let this fact absorb into your mind. This is what has unfortunately come your way. Ok, that's life. You can deal with it. Thinking along these lines can help.

Benzodiazepines

Benzodiazepines are often prescribed for HPPD. They can help alleviate anxiety and even some of the visual effects in some cases. However, Benzodiazepines are addictive and not a long-term solution, nor is it appropriate to use them as a long-term crutch to help the symptoms, as a benzodiazepine addiction is generally worse than HPPD. In the initial phase after having contracted HPPD though, the anxiety can be at its worst, and so they can be useful for that temporary period.