A study involving 63 polysubstance dependent women and 46 controls (participants who were not using substances) used the Benton Visual Retention Test (BVRT) and the California Verbal Learning Test (CVLT) to look at visual memory and verbal ability. This study showed that in polysubstance dependent women, verbal learning ability was significantly decreased, though visual memory was not affected. In addition, alcohol and cocaine use led to more severe issues with verbal learning, recall, and recognition. Memory, reasoning and decision making
Sometimes studies about specific groups in the general population can be informative. One study decided to test the cognitive abilities of participants in rave parties who used multiple substances. To do this, they compared 25 rave party attenders with 27 control participants who were not using substances. The results of this study indicated that in general, the rave attender group did not perform as well on tasks that tested speed of information processing, working memory, knowledge of similarities between words, ability to attend to a task with interference in the background, and decision making. Certain substances were associated with particular mental functions, but the researchers suggested that the impairments for working memory and reasoning were caused by the misuse of multiple substances.Another study that tried to find differences between the effects of particular substances focused on people with polysubstance use who were seeking treatment for addictions to cannabis, cocaine, and heroin. They studied a group of people with polysubstance use and a group that was not dependent on any substances.
The tumors are of tufts of capillary-sized vessels in lobules that are scattered in the skin, and that sometimes reach into the subcutaneous tissue, and have lymph vessels on the periphery. Their growth is slow to begin with, and progresses to a stable size. They show a high rate of spontaneous regression, particularly in congenital and early-onset cases. They typically have a deep nodular component sometimes extending into the subcutaneous tissue, fascia, and muscle, and can sometimes be painful. Tufted angiomas are associated with arteriovenous malformations.The origin of tufted angiomas is not clear but markers on the cells suggest a possible derivation from the endothelial cells of lymph vessels. They are also associated with the local secretion of growth factors that affect angiogenesis and promote the development of vascular lobules. Borderline
Kaposiform hemangioendotheliomas (KHEs) are borderline, locally destructive vascular tumors. They are named after their resemblance to the lesions of Kaposis sarcoma. KHEs are described as locally destructive because they can infiltrate underlying muscle and fat. They are often seen to overlap with tufted angiomas (TAs) but TAs may be a milder, benign counterpart.KHEs show as a red or purple expanding mass of soft tissue, found mostly in infants. Under the microscope KHE is characterised by nodules of tumor-like spindled endothelial cells. Unlike infantile hemangiomas, KHEs have a high mortality rate. Both KHEs and TAs are unique in that they carry the risk of the development of Kasabach–Merritt syndrome. Malignant
Malignant vascular tumors are rare, and include angiosarcomas, and epithelioid hemangioendotheliomas. Other types are  hemangiopericytomas, and lymphangiosarcomas.