In This Issue
Medical Marijuana and Mental Disorders
A suicide attempt by a depressed woman registered to use medical marijuana for pain highlights the risk of psychiatric complications from the rapidly increasing legal use of marijuana. Nussbaum et al. (p. Original article: 778) describe marijuana's relationships to psychotic disorders, depression, impulsivity, and suicidality. Widespread use in the United States began in 2009, when the federal government announced it would not prosecute users of medical marijuana where it has been legalized at the state level. These jurisdictions include the District of Columbia and 14 states, including Colorado, where the suicidal woman lived. Approximately 2% of Colorado's population were registered for medical marijuana in 2010, and physicians there are not required to examine people applying for registration.
Colorado has twice as many medical marijuana users, on a per capita basis, as California (Nussbaum et al., p. 778)
Linkage for Depression on Chromosome 3
Two independent studies focusing on distinct subgroups of patients with major depressive disorder both showed linkage of the disorder to chromosomal region 3p25-26. Breen et al. (p. Original article: 840) found the association among 839 families containing pairs of siblings both affected by severe, recurrent major depression. The linkage discovered by Pergadia et al. (p. Original article: 848) emerged from sibling pairs with major depression in 95 families of heavy smokers. The identified region contains a glutamate-regulating gene and other genes that are plausible for involvement in depression. The review by Hamilton (p. Original article: 783) illustrates the overlap of these linkage results with findings in two earlier genome-wide association studies.
Clinical Guidance: Prognosis for Patients With Prodromal Attenuated Psychotic Symptoms
The risk of developing a full psychotic episode within 1 year was 30% for patients who sought help for attenuated positive and negative symptoms of psychosis at a mean age of 18. The remainder improved significantly, but 40% still had at least one attenuated positive symptom. Social and role functioning also continued to be affected, according to Addington et al. (CME, p. Original article: 800). Processing speed deficits underlay these functional problems in a related study by Carrión et al. (CME, p. Original article: 806). Weiser states in an editorial (p. Original article: 761) that although many people with attenuated symptoms do not have schizophrenia, they are not well and need help.
Infection and Schizophrenia Over Time
Extended studies tracking outcomes in people infected with Toxoplasma gondii and in a group exposed to herpes simplex virus 1 (HSV1) bolster the evidence for associations of these infections with schizophrenia. In a cohort of 45,609 women in Denmark, Pedersen et al. (p. Original article: 814) demonstrated that T. gondii infection increased the risk for subsequent development of schizophrenia spectrum disorders. Prasad et al. (p. Original article: 822) documented losses over 1 year in executive functioning and posterior cingulate gyrus volume in HSV1-positive patients with schizophrenia but not in seronegative patients or HSV1-seropositive or -seronegative subjects without schizophrenia. Connections between schizophrenia and environmental factors are especially promising, notes Brown in an editorial (p. Original article: 764), because many of these exposures are preventable or treatable.
Clinical Guidance: Cognitive Effects of Second-Generation Antipsychotics in Alzheimer's Disease
Patients with moderate to severe Alzheimer's disease who receive olanzapine, quetiapine, or risperidone for the indication of agitated behavior or psychosis experience a decrement in cognitive function greater than occurs with placebo. Vigen et al. (p. Original article: 831) estimate that the decrement ascribable to the antipsychotic is equivalent to 1 year's progression of illness. Devanand and Schultz in an editorial (p. Original article: 767) point out that adverse effects in Alzheimer's patients are quite dose dependent, e.g., occurring with risperidone doses greater than 2 mg/day or olanzapine doses greater than 5 mg/day. Alternative medications, such as benzodiazepines, also have adverse cognitive effects.
