Diagnosis and treatment of psychiatric and behavioural disorders in mentally retarded individuals: the state of the art.

Iwata (1993) scanned every corner of mental-health care for people with intellectual disability. The paper pulled together what doctors, psychologists, and behavior analysts were doing in 1993. It looked at how teams tried to spot and treat depression, anxiety, and behavior disorders in this group.

The review found no single playbook. Clinicians bent standard psychiatric rules to fit people who could not always speak or reason at age level. Some leaned on pills, others on talk or reward charts, and many mixed both.

The big message: diagnosis is messy and evidence is thin. Checklists made for the general public often missed signs in people with ID. Treatment studies were small or missing, so teams flew by habit, not data.

The paper urged readers to blend tools: tweak criteria, watch behavior, try meds only with clear targets, and keep measuring.

Later papers kept returning to the same gaps. Coe et al. (1997) gave a step-by-step way to decide when behavior plans can replace or shrink meds, turning the 1993 “blend ideas” line into a real workflow.

Clarke (2003) and Najdowski et al. (2003) tested new DC-LD criteria meant to fix the fuzzy-diagnosis problem flagged in 1993. They argued the extra rules catch ADHD and psychosis that old checklists miss.

Falcomata et al. (2012) updated the story again, showing that even with new tools many staff still feel lost. Their review says training, not just criteria, is the missing piece now.

If you serve adults with ID and mental-health needs, this paper is your starting map. It tells you why standard DSM questions fall short and why you must add direct observation, caregiver reports, and data sheets. Use it to justify extra assessment time, ask doctors for clear med targets, and push for team training on DC-LD or newer guides.